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anyone have the Universal Digital Dual Sim adapter?

I mean this one....
http://www.2-phones-in-1.com/english/products/universal_digital_dual_sim_II_us.htm
Id like to try this software on my dual sim, just because I can
if so, PM me

I would suggest you send your sims to them to be cut by their machine, I destroyed 2 sims. Other people have reported success, it says on instructions that the metal on sim should not be cut, on many sims there is no chance of it fitting without cutting the metal tabs. I threw mine in the bin, that doesnt mean its no good though.

mine worked fine, cutting went perfect

Yeah, I've used a cut up dual sim with a UK 02-uk Contract and orange PAYG sims. Some people said the O2 doesn't work: I had no trouble.
I very much hope you're note paying 37 euro for it: I got mine for £1.75 from ebay:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=6415916094&ssPageName=STRK:MEWN:IT
However, note that the STK menu is something special: it's a menu that gets loaded up when you load a program called "sim toolkit" built into most phones. Then you can choose your line. The one I bought doesn't have this, you go to flight mode on, flight mode off and it'll switch lines.
Cutting the sims requires a careful hand. Get them cut by machine if you can (the guy i got them from will cut them) but you get templates that you should follow carefully with fine scissors and you shouldn't go wrong.
The instructions say that you DO cut the metal tabs on the SIM, there's no other way, but that does not damage to the sim itself. But be careful, practice and try them one by one - you have something called a "Resume card" that is basically a holder for one of the tiny mini-sims. Try this with each cut sim individually to ensure they work, before putting them in the metal tray. I used a nokia to test.
Don't forget to REMOVE THE PLASTIC TEMPLATE. Jeez, this was so obvious but once you've nervously cut the sim up, you'll forget the transparent guide sticker is still on them. Remove this obviously!
In the Magician it took a lot of messing about to get the phone to recognise both sims, because I think there's not much pressure on the back of the sim in the phone's holder. I stuck a little bit of paper down the back of the metal slide to apply some pressure.
It does work, just persevere!
Vijay
PS I read via google that the STK software drains battery faster. I'm sure it wouldn't, but one review said it did? It's not much more effort.
PPS Don't use a sim copier if you're in the UK (eg 16 in 1). It'll destroy your SIMs, they're not compatible here.

[TIP] Do you get the dreaded simcard error randomly? This might fix it

So two days after acheiving s-off with the new method for the s4 variant with the jb ota, my dad got the random simcard not detected error. After attempting various firmware flashes, it started getting worse to the extent that it showed the simcard icon and the x over the signal bars more often than not, so I tested his simcard in my amaze, and it worked fine. So we figured that it was a physical issue, so I read on another forum that the One X guys were fixing it by applying a layer of clear tape on the back for a tighter fit. So I had a roll of clear duct tape, applied one layer, and for a few minutes, it seemed to work. After handling the phone, the error came back, so I pulled the simcard and applied another layer of packaging tape. Now, its a tight fit, but I was careful that I was inserting it in the best possible angle so that I wouldnt damage the simcard slot. Popped it in there, played with the phone, so far so good.
Obviously this is a bandaid, but I already damaged the simcard slot by sticking a ghetto converted sim to micro simcard in, and because I cut it too narrow, it slid in kind of diagnally, and it bent some contacts, so these micro sim slots are very sensitive if not outright defective. I say this because for the past two days, I have searched google for thebproblem, and although this isnt unique to htc, there is a very high rate of simcard slot failures for the entire "One" line, including the new 'One'. I may contact htabout this, because this seems like a wide spread problem, and I already had to order a new slot, and it cost me $80 to have it soldered by the guyd at the Jacksonville,Fl branch of CPR, and as good as the technician was, it took him a second try to fix it, and weeks later, it started happening randomly, even though nobody touched the simcard. So thats the info that I have, if you have any questions regarding this issue, post it here so that everyone can see it for future referrence. Goodluck.

How to fix Galaxy S4 "Sim card removed" error

I'm sure plenty of you have had the dreaded "Sim card removed" error (as shown in the attached image) on your S4. I started getting this message mere months after purchasing my secondhand AT&T S4 (no warranty). But fear not, with about 20 minutes of your time and less than a dollar worth of parts, you can fix it!
(1st attached pic)
Why Does This Happen?
This error is usually due to a faulty connection between the motherboard and the SIM / MicroSD card tray. Likely it is due to a bad solder job on that connector.
Does a new SIM Tray fix it?
Extremely unlikely. Purchasing a new SIM tray will likely be wasted money. (EDIT: A new motherboard may fix the issue, and several people have had success with a new SIM tray)
How do I fix it already??
This is what you'll need:
Your S4
A micro Philips-head screwdriver
Scissors
A foam earplug (or something of similar texture)
Step 1: Disassemble your phone. Pull off the back cover, remove the battery and cards, then unscrew all 9 of the micro Philips screws. Then, take your fingernail and pry off the bezel from the rest of the phone, and slowly work your nail around the bezel until it pops off. (Don't force it!)
(Attached images 2, 3, and 4)
Step 2: Use your scissors or a razor blade to cut a section off of the foam earplug which is about the width of two dimes. I also cut a 1/4 segment out of mine so you don't see it sticking out when you put the bezel back together, but you don't absolutely need to do that.
(Attached images 5 & 6)
Step 3: Press down on the connector for the SIM / SD Card Tray until it "clicks" into place. (It may not click if it is still somewhat in place) This is the connector which has a bad connection.
(Attached image 7)
Step 4: Place your piece of foam on top of the connector in a way that it is right beside but not overlapping the camera (as pictured)
(Attached image 8)
Step 5: Replace your back cover, making sure not to move the foam you just installed, press down on it in multiple locations until it pops back together all around, and screw it back down. Note: if the bezel appears to be bulging out, your foam is too thick! This won't cause any problems, but it will be a noticeable bulge on your phone.
(Attached images 9 & 10)
Step 6: Replace your back cover and enjoy! Note that if you continue to receive the error, you may need either a thicker piece of foam, or you may need to reposition the foam, or even just press down on the connector a bit more before installing the foam.
Thanks to the folks over at Android Central in the thread entitled: Galaxy S4: Major problem - SIM card not detected for info on how to fix!
After applying this fix (took me three times to get it right) I have not seen the SIM card removed error in almost two months!
Post your success stories!
EDIT: A year after I posted this, and people are still using this thread to iron out their issues. I'm glad I could start up a conversation about this problem, with many good suggestions as to possible fixes. I don't use my S4 anymore, but it makes for a great backup phone!
Anyway, I just wanted to let anybody who is looking for the answer to this problem know that my fix may or may not work for you. It worked in my case, but several commenters have noted that the problem has remained in their situation. I would like to point out a few helpful comments and possible fixes right here so you guys don't have to go searching through pages of comments to find different solutions.
Best solution by far is by @Gonemad to re-flow the solder to that connector and to the NFC chip using a heat gun. See post #98 on page 10 and Post 114 on page 12, with a guide on post 122, page 13.
A replacement motherboard may fix the issue as well, but that's assuming you're getting a new one and not a used one. With used, the replacement board may do the same thing!

many of us have shimmed the connector 1000 different ways and still get the error. oddly enough, for me the only thing that has reduced errors was removing my sd card.

iateshaggy said:
many of us have shimmed the connector 1000 different ways and still get the error. oddly enough, for me the only thing that has reduced errors was removing my sd card.
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That's interesting, and a shame. There's not enough room on my phone for all my stuff, I need that extra 32gb!

"Does a new SIM Tray fix it?
Extremely unlikely. Purchasing a new SIM tray or even a new motherboard will be wasted money."
It did in my case. I got a sim/sd card tray from a Verizon S4, put it in my AT&T S4 and it worked great!

This problem is extremely annoying. Purchased a new tray too, and for a couple of days thought the problem is fixed. Nope. 5 days later same stupid message. I had already tried putting more support on the connector which did not fix the problem. They could at least make a cancel button on it instead of just "reboot". Will try without sd card. Apparently this happens on ALL high-end samsung phones. I am adding crapsung to the "never again" list (in addition to LG now).
If removing sd card doesn't fix it then it will either be new mainboard (they go for around $100 CAD shipped) or a new phone if I have the money. Nexus 6 looks good now. Don't buy crappy Korean brands. Even Chinese brands seem more reliable.

Question: Since you say that you've already replaced the sd/sim tray and the problem returned, did you try putting another sim card in there to make sure that it's not the sim card that's the issue?

Yes, new sim did not solve it. Now i am actually trying earplug thing. So far so good (2 days), but as with any other method the message is expected to pop up again. I am thinking i did try to add support before, but only for the connector part. Earplug will press on all the components around the connector and the connector itself. Will see. I did cut out a thicker piece than in the OP, and made a cut on the camera side instead of oppoate (like in OP).
Buyimg new mainboard seems like a waste of money now too. Since so many devices have this problem chances are another mainboard will be the same.
Edit: with or without sd card - same thing.

It's known that the IMEI numbers with the last 6 digits in this range: 000000 - 560000 have been known to have this issue. Mine was in that range and had the issue. I think the mainboards outside this range are fine.

Mine is not in that range.

Thanks a lot

It took me quite a few tries with the earplug foam to get it right. Finding the correct thickness and shape was the biggest thing. Eventually I got it right and I haven't had the issue return even once since. I'm glad some of you were able to get your phones to work by just swapping the SIM tray, that's pretty easy to do. I don't think I would even consider swapping the motherboard on a 2 year old phone, might as well just get a new phone at that point.

Sean89us said:
It took me quite a few tries with the earplug foam to get it right. Finding the correct thickness and shape was the biggest thing. Eventually I got it right and I haven't had the issue return even once since. I'm glad some of you were able to get your phones to work by just swapping the SIM tray, that's pretty easy to do. I don't think I would even consider swapping the motherboard on a 2 year old phone, might as well just get a new phone at that point.
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Good to hear that this is working for some users. I just went with the M9 about a week ago and am going to give my mother my S4. She wouldn't have any idea how to handle any sim errors so when I get some time, I'll be buying an earplug or two.

It has been 9 days and the error hasn't returned. Today i put in a thiner peice to get rid of the bulge on the back. Will see how that holds up, but so far so good. Thanks to the O.P.
As for the mainboard - I never loxk myself into a contract with a discounted phone, not that Wind Mobile Canada has an option for it. So i paid almost 600 CAD for this puppy and expected it to last. For me $100 is not bad for a fix compared to at least $600 for a new phone. Only if it was for sure, but is seems like a gamble to buy a new board. BTW my phone was locked to rogers so I had to unlock it and enable AWS band.

I would get(have tried other phones) but for all its bad the S4 is hands down the most durable and usable phone I have ever owned. I like my nexus 5, but it is a very fragile unit, and on its second screen replacement due to minor drops that the S4 takes with aplomb. I like the phone so much I have bought a used one off ebay just in case this one ever fails. MHO

fargonaz said:
I would get(have tried other phones) but for all its bad the S4 is hands down the most durable and usable phone I have ever owned. I like my nexus 5, but it is a very fragile unit, and on its second screen replacement due to minor drops that the S4 takes with aplomb. I like the phone so much I have bought a used one off ebay just in case this one ever fails. MHO
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I'm right there with you. I still love my S4, despite the SIM error and somewhat slow updates from Samsung / ATT. It's getting older but my phone is still very fast, has a beautiful 1080P AMOLED screen, takes awesome pictures, and now it's even running Lollipop! The only thing that might convince me to switch phones anytime soon is if the 2015 Nexus 5 refresh has a 5" - 5.2" screen (5.5"+ is just too big!), USB Type-C and the specs blow me away. Since that probably won't happen, it looks like I'll be using my S4 for a few more years.

I don't have these earplugs foams at home.. Which other material can I use for that?

I can't say anything else will be the same material. Just buy earplugs at a dollar store or something. They are cheap.

Mine had gotten really bad, to where it was giving the "sim error" message a good six or eight times a day. Did the earplug thing...didn`t fix squat. I took a narrow strip of a business card and "shimmed" the sim card in it`s slot (like many others have), but I made my shim extra long and folded it over a few times on top of the sim card receptacle as well. Been two days and so far so good. We`ll see how it holds up.
I had actually contacted Samsung about the problem and they claimed they had no knowledge of it`s occurrence. I emailed back and they said "we really have no idea what`s causing it. Sorry." I would call it a design flaw as every single person I know personally with an S4 has the problem, and there are hundreds upon hundreds of tales on the ol` internet about it, and even Samsung can`t fix it.

I've used this solution after my s4 gave the "sim card removed" error 5 times this morning. I used a piece of power sponge i.s.o. an earplug. Since then no error. If error occurs i'll respond again.
Thanx Sean.

I was having this problem. I did this fix but just used some folded up plastic wrap. Hasn't happened again yet.
Sent from my SAMSUNG-SGH-I337 using XDA Free mobile app

Moto X 2015 Pure XT1575 Disassembly Teardown Video

https://www.youtube.com/watch?v=vuewklttaSc&feature=youtu.be

Awesome. Not bad. I wish the back panel wasn't attached with adhesive. Makes it much more difficult to change it out on a whim.

sooooo get moto care is what i'm thinking after watching that

I get a warranty match by buying the phone with my visa card, so one year from moto one year thru visa. I skipped moto care

After watching that I cancelled my Best Buy order which still hasn't shipped. I refuse to buy another phone that basically has to be thrown away when the battery craps out. Glued on back is just ghetto.

demi9od said:
After watching that I cancelled my Best Buy order which still hasn't shipped. I refuse to buy another phone that basically has to be thrown away when the battery craps out. Glued on back is just ghetto.
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Sorry to say but it seems like most manufacturers are starting to go this route...the same with weeding out microSD support.

iazybandit said:
Sorry to say but it seems like most manufacturers are starting to go this route...the same with weeding out microSD support.
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Yeah it's a shame. I'll probably end up sticking with my M8 or picking up a G4 once a fully functional AOSP ROM is released. I do hope HTC can pivot and release and more Nexus/Moto type budget flagship next year with the M10.

That's not nearly as bad as I imagined.
As soon as I figure out how to solder in the mod chip, I'll be set.

Did they discover if the pure has dual sim hardware?

It has a dual sim tray but not sure if the software or the sim reader on the US variant is capable of making any use of dual sims

That's what I mean if the teardown revealed if the phone has the hardware capable of dual sim operation ie multiple radios.

toyanucci said:
That's what I mean if the teardown revealed if the phone has the hardware capable of dual sim operation ie multiple radios.
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Click to collapse
The video is just that...a tear down. If you watched the video, it doesn't go anymore in-depth other than opening it up and putting it back together

I looked inside sim tray slot for hardware for second sim don't look like it's installed

I'm thinking it might have the hardware to support it, the reason I say it is because the sim slot on the board is double the size of what it regularly is (even considering the fact it has an SD reader, its on the underside of it), and I don't think they would want to solder two different type hardware onto the board, its not cost or time efficient. I think if out of the box it doesn't work, it is probably disabled from the software, however I will pry off the plastic tab on the sim tray and try it myself with dual sims and see what I get.

Actually just took a closer look inside the sim slot, and there are solder points on the board where the pins to touch and read the second sim should be installed but they are not. All you would need to do I guess would be to take the metal shield covering that area off by using a head gun to de-solder the corners or by cutting it off from the top and then solder a second set of the pins onto the board in its designated slot. After that I don't see why it would not work.

Looks way easier than some phones I've watched. I wish he would have removed the battery Wonder if we will see any custom or higher capacity batteries in the future for modders to use. Also if you have motocare I don't see why they won't replace the battery just file a claim before the 2 years are up and say the battery is awful and get another. I don't see the battery life crapping out in 2 years.

I guess the S6's and Notes are ghetto since the glass backs are glued as well
Sent from my SM-G920T using XDA Free mobile app

Looks like room for a bigger battery and the housing design seems better suited with a replaceable battery design and cover. Seems an odd design decision since no unibody contraint.

Glass doesn't do clips. Glued plastic is ghetto. They simply want to sell new phones every year and planned obsolescence is the easiest way to do it.

iazybandit said:
Sorry to say but it seems like most manufacturers are starting to go this route...the same with weeding out microSD support.
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Needs to be banned.
---------- Post added at 12:13 AM ---------- Previous post was at 12:13 AM ----------
demi9od said:
Glass doesn't do clips. Glued plastic is ghetto. They simply want to sell new phones every year and planned obsolescence is the easiest way to do it.
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Also needs to be banned

Swap a good donor motherboard into a G930X LDU (Live Display Unit)? VERY HARD.

Hi,
The question is: Can a Live Display Unit (LDU) version of the S7 be made a fully functional S7 by swapping out it's non-useable motherboard with a good motherboard from a broken donor S7, and what would be involved to make this work?
I am posting and answering my own question here in the hope it will provide answers to various other posts I have seen in the S7 and the S7 Edge sub-forums. The questions and the answers are relevant to both versions of the S7.
Background:
I am a semi-retired technically oriented handy fellow who is in his early 60's, living on a modest income. As of this last summer (2017), I was still using the Galaxy S4 that I had gotten new in early 2014. The S4 has been remarkably durable, and is still working like the day I bought it, but it's just slowly becoming more and more obsolescent. The only thing I have had to replace over the almost 4 years I have had it was a tempered glass screen protector that did it's job and sacrificially protected my screen, a few cases that wore out, a frayed charging cord, and a few replaceable Li-Ion batteries that no longer were keeping their charge long enough.
However, the S4's limitations of only 16GB of onboard storage, only 2GB RAM, the increasing (relative) slowness of it's 32 bit quad-core processor when running multiple current apps, and the fact it is stuck at Android 5.1 were becoming increasingly an irritant.
I determined the time had come to upgrade my phone. I didn't mind signing a new contract and getting a new phone as I've always had access to reasonably priced phone plans, but I don't like the idea of having to pay a monthly additional fee of $30-40 to lease a phone that has to be returned after 2 years or purchase a phone at full retail cost with even higher monthly payments and/or a big down payment. So I determined that somehow I would have to find a "deal" on a like-new good fairly current but used phone.
I looked around at the cost of the then new S8s and could not justify paying $800 or $900 USD on a phone. I then looked at the 2016 flagship, the S7, but they were still selling then for $300 or more used. I didn't want to get anything older because I wanted to be on the most current version of Android and have at least 32GB of on-board storage, 4GB of memory, and a good 64bit quad-core processor. I also wanted to stay with Samsung, because I was familiar with their "version" of Android and knew them to usually have a fantastic build quality (except for their debacle with the self-igniting Note in 2016).
So I started out looking at how I could acquire a like-new used S7 for about 1/2 of the going rate -- or about $150 USD. I have repaired my own "smart" cell phones in the past -- but that was back in the days when they were held together by screws. I hadn't needed to open up my S4, and had not personally seen the insides of the ever-more-glued-together phones that have been produced since, although I had kept somewhat current by watching various YouTube videos of tear-downs of new phones as they came out. As I said earlier, I am a technically oriented handy fellow, so the thought of learning to deal with the hardware and assembly methods used in the newer versions of smart phones didn't scare me (at least not very much). If someone else can work on them, then I can educate myself and do it too. Thus I determined that the way to get my new phone at a reduced price would be to find one and repair it. So I started my research of the S7.
Research:
Through my research, saw that there are a lot of really busted up S7 phones out there that do show solid signs of life when plugged in (although the screen is broken and non-functional). These phones power up, hold a charge, make the appropriate booting sounds, and the LEDs at the top and bottom light up during the boot process. All of this indicates a functioning motherboard. Additionally, many of these badly broken phones with functioning motherboards also have readable ESN/IMEI numbers on their backs, and so their ESN/IMEI numbers can be verified as non-blacklisted and non-leased. Basically, you can tell if the broken phone you are buying has an activatable motherboard in it or not before you purchase it.
I saw that S7 phones with blacklisted ESN/IMEI numbers or that were blocked because of being on-lease but that were in like-new condition were still selling at prices in the mid-to-high $200s, which is more than I wanted to pay. For ethical reasons I also didn't like the possibility of potentially supporting thieves by buying stolen stuff they were selling. So it was looking like I was going to have to look at paying for a broken phone and a $150 replacement screen assembly and miscellaneous other needed parts, at a total cost of $200-$225. This still didn't fit in my desired budget.
I then learned of the existence of the Live Display Units (LDUs) that come up for sale on Ebay from time-to-time. These LDUs have special motherboards in them that were manufactured without the cellular radios that fully functional S7s have. This was done by Samsung to reduce the thefts of display models at the stores that sell their phones. Other than the lack of cellular capability, the LDU models are fully functional -- working screens, cameras, speakers, wi-fi, apps, they just can't connect to cellular towers and so can't be used for phone calls or for mobile data purposes. They also have a "special" firmware version installed on them that prevents them from being turned off, and automatically wipes their memory and restarts the "demo" programs after a certain amount of time has elapsed. Most of these LDUs are in like-new condition -- never having been in pockets or purses getting scratched up, never dropped, never gotten wet, etc. They might have some screen burn-in issues -- but that is tolerable to me. I saw them selling for around $110 USD. The LDU models have an "X" suffix. In the case of the S7 models, the LDU model numbers are G930X (S7) and G935X (S7 Edge).
So I got to wondering if it might be possible to combine the two otherwise useless phones and make a like-new S7 out of them by swapping a fully functional motherboard from a donor S7 into an LDU like-new "body" with a good screen. I determined to try it out, and promised to document the results of my experiment on the various posts I had seen asking similar questions -- but didn't have answers. (I'll be going back to those posts and posting a link to this one.)
Preparation:
I watched a number of tear-down and repair videos on the S7, and purchased a collection of the appropriate specialized tools from various sellers on Ebay (some directly from the manufacturers in China, some from US sellers). These specialized hand tools are fairly inexpensive -- for example one of the most useful tools when ungluing glass from the frame is a set of plastic guitar picks -- some use a sacrificial deck of playing cards (plastic guitar picks can be wiped off and reused). I knew that I was going to have to make do without some of the equipment the "pro"s use -- like vacuum tables, heating ovens, UV curing stations, etc. I would have to make do with other methods to hold the phones, to heat them, and use LED UV flashlights or UV fluorescent bulbs in existing fixtures for UV glue curing.
On to actually "doing it":
I purchased a couple of functioning G930X LDUs on Ebay in good cosmetic condition. One of them had some minor screen burn-in, the other was in a boot-loop. I didn't care about either issue as I wasn't going to keep the motherboard, and minor screen burn-in doesn't bother me, as it is really only noticeable when the screen is mostly white, which isn't often in real-world usage. I got these for about $107 USD each. Far less than just a replacement screen assembly would have cost. For some reason, the Edge versions of the LDU's were going for much more, some close to $200, but I wanted the non-edge version anyway.
I then purchased a couple of badly busted up S7 donor phones with functioning motherboards and clean ESN/IMEI numbers, which I got from the sellers and verified prior to the purchase. I was able to get these "parts-only" phones for around $45-60 USD each.
I then got to the actual work of opening up the phones and attempting the motherboard swap. Here's what I found out:
Well, my first attempt didn't work out the way I had hoped, but I learned A LOT.
Firstly, to replace the motherboard on the S7, you pretty much have to completely disassemble all the parts contained on the back of the metal middle-frame. An exception to this is the bottom daughterboard which normally can be left in place when replacing a motherboard. This part of the work turned out to be fairly easy to do once the back glass was removed. I cracked the first back glass I removed, but was able to get them off in one piece after that. Luckily, the replacement glass backs are not very expensive (even the ones that come with the camera lens and adhesive pre-installed are less than $10 USD.)
In addition to the motherboard, I found the following parts are different between the North American (NA) S7 models and the demo G930X LDU model. This will likely be true for the G935 Edge models too:
1. The plastic covers at the top and bottom of the phone that include the molded-in antennas are different between the LDU and the NA models. I think that they might be the same as the European versions though. This was not a problem, because I could simply use the parts from the non-LDU donor phone that had the bashed in screen and back.
2. The phone speaker (not to be confused with the earpiece speaker) is different than the NA versions. The LDU contained the European version. I don't know if this is really so different that it wouldn't work, but, if you ever want to send it to an official "factory" service place for some reason, they might reject the phone because it doesn't contain the "proper" parts. Again, this is not a problem, because I could use the speaker assembly from the North American non-LDU donor phone.
(I suspect one of the reasons for the differences in the antenna and speaker parts has to do with tighter European RF (radio frequency) emission standards)
3. Here's where the big problem occurred -- the LDU also has a modified bottom daughterboard (this is the daughterboard that has the charging port and headphone jack on it). This daughterboard on a regular S7 contains antenna connections and circuitry that is missing on the LDU model. That wouldn't be an issue except It turns out that, on the S7, this bottom daughterboard includes the leads, sensors, and LEDs for the "soft" buttons to the left and right of the Home button. What this means is that, in order to swap this bottom daughterboard out, you have to remove the screen assembly from the front of the phone so you can expose and release the softkeys that are part of this daughterboard and that cannot be detached from it. I understand that this is true for both models of the S7.
Getting the screen assembly loose from the adhesive that bonds it to the metal middle-frame without damaging it, even with using heat, is a very tricky and failure-prone operation. The adhesive is incredibly strong and the slightest wrong amount of pressure will fracture the fragile LCD that is on the bottom of the screen assembly (the LCD is actually what is glued to the middle-frame). Break the LCD and you've got a dead $150 USD front screen assembly, basically making the LDU a useless investment. The LDU motherboard isn't worth much. Basically what you have left is the battery, the frame, the Qi and NFC antenna assembly, the cameras, and possibly the back glass if you managed to get it off without breaking it. None of these parts are very valuable.
I failed at my attempt to do this, and must have cracked the LCD -- although I was very careful and worked slowly. I couldn't see a crack, but it wouldn't light up after I reassembled the phone. I was careful not to damage the leads on the display when loosening the glue on the screen edges (you have to be extra careful on one side where the leads are routed through the middle-frame close to one of the edges) -- so that wasn't the cause of the failure.
As the euphemism goes -- "hindsight is 20/20". I now think the correct approach is to leave the LCD and digitizer glued down to the middle-frame, and instead (with heat) separate the front glass from the digitizer and LCD using the wire separation method you can see being done on YouTube in videos where just the front glass is cracked and being replaced (the LCD and digitizer are still functional). Once the glass is separated, the soft keys are exposed and the daughterboard can be swapped out. You would then have to use the specialized UV activated glue to reattach the glass to the digitizer and LCD. I seem to recall that there is a plastic film polarizing filter that often gets damaged during the separation process and has to be replaced, along with the seals for the top and bottom, and the seals for the sides of the glass. The glass, seals and the filter are not that expensive. However, doing this screen disassembly process is tricky too (but not as bad as trying to preserve the LCD when attempting to remove the entire assembly).
I don't recommend others go this route (attempting to use an LDU for it's frame and display assembly) unless they have experience successfully being able to remove and install the front glass on these phones.
With it's fully curved sides, the S7 Edge (G935) version would be more difficult to get the front glass removed and replaced. I know I would want to practice on a couple of S7 Edge phones with fully broken displays before I attempted it on a good display..... It is certainly not a project for the faint-of-heart.
The glass separation for the regular G930 S7 doesn't look too difficult, as long as a person uses (moderate) heat, is careful, and has patience. I have one more G930X LDU that I purchased, so I am going to find out. I'll try to update this post with the results of that effort.
International/European versions of daughterboard are different than North American
Something I did learn that will be of interest to anyone attempting to swap motherboards between an international/European version of the phone and a North American version of the phone is that there IS a difference in that same troublesome bottom daughterboard between the two versions of the phones. I know this because I asked a parts supplier, and they informed me that there are two different versions of this daughterboard -- one international/European and the other North American. (I don't know which version is used in the Chinese domestic version of the S7, or whether or not there is a difference between the versions used in the various Asian markets. Hopefully one of the experienced Asian posters will know and reply to this thread with the answers.)
UPDATE (12/16/2017):
I don't know exactly what the differences are in the daughterboard, but they are slight. I recently got a G930FD parts phone with a bad motherboard, and discovered that I could use the European daughterboard with a North American motherboard and antenna set -- you should switch out the antenna wires that go from the motherboard to the daughterboard (the colors are reversed), and it works just fine
Well, it turns out I was wrong about the European daughterboard being compatible with the North American motherboards. Everything on the phone works EXCEPT the wireless radio can't get a signal lock, and eventually shows an "x" on the signal bars indicating that the radio has turned off. I tried this with multiple T-Mobile SIM cards, and worked with a tier 2 T-mobile phone technician trying every possible thing to work around this. Bottom line, it looks like the European version of the charging port daughterboard is only compatible with the G930F and G930FD motherboards. Oh, well. It was worth a try. I am now looking for a working G930F or G930FD motherboard to get this phone working again. I am also looking for a good North American G930A, P, T, V frame and good display (or just a good complete screen full assembly) to make a whole phone with the good T-mobile motherboard I have.
Samsung learned their lesson regarding this daughterboard
One other point I learned from a cell phone technician -- the issue of the front softkeys being part of this bottom daughterboard has been fixed in the S8. It seems Samsung learned "the error of their way" with this design. Whenever this daughterboard needs to be replaced on an S7 due to a charging port issue or headphone jack issue it requires removing the front glass to get the job done -- making the work a lot more involved and costly for Samsung's own repair staff, as well as all the authorized in-warranty carrier cell phone repair centers.
A lot of grumbling has occurred. due to this design. I am sure the post-warranty non-authorized repair centers are also pleased that this design ended with the S7. Their customers can't have been pleased at the elevated post-warranty charging port repair costs this design has caused....
Success in a non-LDU motherboard swap:
After failing to be able to use the first LDU to build a useable S7 phone by swapping it's motherboard with a good motherboard (with a clean ESN/IMEI number) from an S7 with a badly broken display and back (and scarred up middle-frame), I was able to use another North American S7 that I found with a good display, but a bad motherboard. The swap was pretty easy to do, and I wound up with a functional S7 at the end, for much less than I would have paid for a refurbished or a good used S7. I did have to deal with bypassing the FRP lock on the good motherboard because, of course, when the screen was broken, the previous owner couldn't log out of their Google account, so the FRP lock came into play once the phone was factory reset. That "adventure" is covered in another post I made a few weeks ago. Doing this first S7 motherboard swap has been an invaluable learning process as well -- one that I hope to be able to leverage and turn into a profitable sideline/hobby in doing future swaps and repairs. I find I really enjoy working on these intricate pieces of electronic equipment.....
A cautionary tale:
BTW, there's an interesting story (at least to me) as to why the motherboard on the S7 I used as the "screen donor" was damaged. I think it's a cautionary tale of what NOT to do to your mobile phone....
The previous owner had not used the "sim tray removal tool" to eject the S7s SIM tray, and had snapped the top off of the sim tray attempting to brute-force it out. They then went on to use what must have been a screwdriver, knife and/or nail file to try and pry the rest of the tray out, and in the process broke off most of the electrical connecting "fingers" on the motherboard that contact and connect to the SIM and MicroSD cards. I only discovered the extent of the damage once I had removed the motherboard and gently pushed the remnants of the broken SIM tray out and was able to see what had been done. In fact, I found the SIM card was still in place within the bottom 3/4 remnant of the broken SIM tray, which was also still very much in place. The SIM card, which is located at the bottom end of the SIM tray, also showed evidence of how much digging and gouging the owner or the seller had done trying to get the broken tray out -- they had dug around that deeply within the slot on the phone that they scratched and deeply scarred up the SIM card.
Otherwise this motherboard was functional -- unfortunately since it couldn't connect to the SIM card, it rendered the motherboard almost as useless as an LDU motherboard. I think the Ebay seller who sold me the phone had done some further damage trying to get the phone to work. The story he told me was that the original owner's kid had jammed something down inside the slot -- this proved obviously not to be the work of a small child.
A last thought regarding using LDU and other semi-functional motherboards
One last thought regarding LDU and other semi-functional motherboards -- these boards can be reflashed with functional firmware, and the motherboards can be probably be used in phones with broken displays as always-on smart home controllers, possibly as media players, or whatever else a person can imagine with a wi-fi capable Android device. I am planning on using my old S4 in this fashion -- connected to a USB OTG and MHL enabled docking station so it can be connected to an external display and sound system. Samsung made a special docking station just for the S3 and S4 (and probably the Note 2) that makes this possible, and can be found used online for much less than it originally cost. I know that the S7 is also OTG enabled, so with it's included adapter or a generic OTG docking station or cable you can do similar stuff.
My hope is that this post is both useful and interesting.
Good luck with your adventures with the Galaxy S7!
Philip

Very nice adventure Sir
I have S7 G930FD with broken motherboard but good display LED screen
Can I swap the broken 930FD's motherboard with Working well 930F's one?

Help
Hello Phillip,
My S7 screen was damaged and i acquired a LDU and attempted the motherboard and daughterboard swap. The screen came come and I it would seem that everything was fine....except that the touchscreen is unresponsive lol....in your experience is it a software/firmware issue or did i damage the digitizer? could it be i did not "reconnect" it properly. Plz help

agusto888 said:
Very nice adventure Sir
I have S7 G930FD with broken motherboard but good display LED screen
Can I swap the broken 930FD's motherboard with Working well 930F's one?
Click to expand...
Click to collapse
I believe that would work. The daughterboard and antennas should be the same for both the FD and the F models.
Let me know how it goes.
Good luck,
Philip

Meesh8 said:
Hello Phillip,
My S7 screen was damaged and i acquired a LDU and attempted the motherboard and daughterboard swap. The screen came come and I it would seem that everything was fine....except that the touchscreen is unresponsive lol....in your experience is it a software/firmware issue or did i damage the digitizer? could it be i did not "reconnect" it properly. Plz help
Click to expand...
Click to collapse
It isn't a firmware issue because the F motherboard you used should have F firmware on it. If you tried to flash the FD firmware onto the F motherboard you will likely run into serious problems because the hardware for the second SIM card is not present. You could simply re-flash the F firmware onto your motherboard and eliminate this as the issue. Make sure you use the non-HOME CSC version so your phone will be completely set back to factory settings. The HOME version of the CSC firmware section preserves some of the user data. The non-HOME version resets almost everything.
It's hard to say what the problem is without having the phone to look at. It would seem strange that you would have somehow broken the digitizer but not the Amoled display. However, if you nicked the screen's cable when you removed it from the LDU, that might be causing the issue.
I would try to disconnect and re-seat the display cable and see what happens -- you've got nothing to lose at this point. Make sure you don't force the connector into place -- it should connect easily once you get it lined up correctly. If you forced it, you may have bent some of the pins on the motherboard or the ribbon connector and that could be causing your issue. Look closely at both under a strong magnifier to check this. If something is bent, sometimes it can be unbent, but you'll need magnification and needle-sharp tools to manipulate the tiny contacts.
Good luck,
Philip

phreich said:
I believe that would work. The daughterboard and antennas should be the same for both the FD and the F models.
Let me know how it goes.
Good luck,
Philip
Click to expand...
Click to collapse
Fortunately I've found 930FD's motherboard. My S7 comeback to live again.
I've experienced damaged motherboard twice. After played around with TWRP custom rom.
Do bad flashing customrom from TWP, indeed able to damage the motherboard sir?

agusto888 said:
Fortunately I've found 930FD's motherboard. My S7 comeback to live again.
I've experienced damaged motherboard twice. After played around with TWRP custom rom.
Do bad flashing customrom from TWP, indeed able to damage the motherboard sir?
Click to expand...
Click to collapse
I don't use TWRP. I flash the motherboards with Odin. In my experience, you can usually resurrect a motherboard with corrupted or wong firmware by reflashing it with the proper factory firmware using Odin.
Just curious, where did you find the 930FD motherboard, and how much did it cost? Do they have more? I also am looking for a 930FD motherboard.

phreich said:
I don't use TWRP. I flash the motherboards with Odin. In my experience, you can usually resurrect a motherboard with corrupted or wong firmware by reflashing it with the proper factory firmware using Odin.
Just curious, where did you find the 930FD motherboard, and how much did it cost? Do they have more? I also am looking for a 930FD motherboard.
Click to expand...
Click to collapse
Already try flashing proper stock rom via odin with no luck. Sending them to official samsung service center : they also cant flash the stock firmware. I am quite sure it was the symptom of damaged Emmc UFS
I live at Indonesia. Got the working mobo from local online shop, I dont think they can deliver overseas.
The FD mobo cost $125 and the F cost $90 in online shop.
In offical samsung service center, the FD mobo cost $240

Hi Philip,
converting an LDU to a full working smartphone is possible just taking the back out and if you don't mind loosing the two bottom touch buttons: https://www.youtube.com/watch?v=KnwfCc5Y0H0
You could then install the Simple Control App to have the soft buttons enabled so you could have all the functionality from the two touch buttons you loose: https://play.google.com/store/apps/details?id=ace.jun.simplecontrol