Database Info

No SIM Card

Hey everyone, I am a Galaxy Nexus user but my brother got an old Roger's S2 LTE that he wants to put on a non-Rogers network (same one I am on with my GNex). However we are having a weird issue where if we insert the original (deactivated) SIM that came with the phone it detects it. But if we put in either mine or his own it just always says "No SIM Card". I even have a pay as you go AT&T SIM that wont work in it either. So far I have flashed CyanogenMod and tried the UCLF6 radio as well as the Rogers ICS Radio UXLF3 from this thread http://forum.xda-developers.com/showthread.php?t=1754473
I should note that when my brother originally inserted his SIM he got the unlock screen and paid to unlock it through cellunlocker.net and it was recognizing his SIM at that point. Since then however we have had no luck. He even replaced the SIM card board with a new one.
Any ideas? I am leaning towards hardware issue but its odd that it still reads the original inserted SIM

did you try to go back to stock firmware and see what happened

Yep. I'm pretty sure its hardware. I got it to read again but still no signal. I have it reading my AT&T card now but again still no signal.
In fact even without a SIM card in if I search for Network Operators nothing comes up. If I do the same on my GNex I get a listing so its looking like this phone is no good
EDIT: Just realized who responded. Your threads were VERY helpful for me! Thanks so much... I'm still not convinced the phone is toast... I have a friend with a GNex on Rogers (I'm on MTS) so I will see if I can borrow his SIM and see what happens

WoodroweBones said:
Yep. I'm pretty sure its hardware. I got it to read again but still no signal. I have it reading my AT&T card now but again still no signal.
In fact even without a SIM card in if I search for Network Operators nothing comes up. If I do the same on my GNex I get a listing so its looking like this phone is no good
EDIT: Just realized who responded. Your threads were VERY helpful for me! Thanks so much... I'm still not convinced the phone is toast... I have a friend with a GNex on Rogers (I'm on MTS) so I will see if I can borrow his SIM and see what happens
Click to expand...
Click to collapse
agree, not the phone, the only way to make sure of anything is to restore to stock and do all the testing from that point on
edit: dah, its the radio, what freq is the new sim card on that wont work, is it the same as T-Mobile
edit: maybe not radio, think its like rogers, could be network settings

Actually both MTS and Rogers use the same towers so the phone should be set properly.
I've got it reading my MTS SIM now but cant pick up any networks. Its set to LTE/HSPA/GSM (Auto) and MTS is HSPA.
Is there anything that could be done to the IMEI of the phone to sort of "blacklist" it from working on any network?
Here is where I have tested from so far:
Stock before I did anything to the phone (Stock rogers GB)
CM9 Nightly
Stock Rogers ICS
SkyICS
I have also tried both the lastest AT&T Radio as well as the latest Rogers Radio. With my GNex both myself and my friend on Rogers use the same Radio (UGLC1).
At this point it seems either the radios arent working at all or the phone is blocked somehow
EDIT: Info on the MTS network... Found on the FAQ on their site:
Any unlocked devices (i.e. devices that are not tied to a specific carrier) will work with MTS SIM cards (on the MTS 4G network). However, carriers such as Rogers, Bell and Telus lock their devices to work with only their SIM cards and these devices will not work with a MTS SIM card. Similarly, MTS intends to lock our devices to our SIM cards. Therefore, our devices will not be usable on another carrier's network.
Please note that any unlocked device must support 4G North American Frequencies (850Mhz), older GSM devices will not function on our new 4G network. You can find out if your device is 4G compliant by reviewing the phone's settings.
Click to expand...
Click to collapse
Also this link: http://www.howardforums.com/showthread.php/1711666-MTS-4G-frequency

UGLC1 never seen that radio for the skyrocket
edit: oh, for the gnex
did you try the *#2263# menu

Yes when I try that menu (*#2263#) it doesnt do anything. I can do *#*#4636#*#* when on CM9 and it works but on stock and SkyICS it just FCs when I select "Phone Information"...
I am going back to Rogers Stock ICS right now. Gotta head off to my engagement party but will likely be back at it tomorrow

shouldn't forceclose, redl and try reflashing x2 the rogers radio, wipe/format x3 in cwm b4 going back to stock ics

Will do first thing tomorrow (or tonight if I'm still in any shape to do so )
If anyone reading this thread has a stock Rogers phone can you turn it off, take out your SIM and then boot it up without a SIM in it and then do a Network Search and see if anything comes up? On my GNex I get networks but on the S2 LTE I dont. In fact I have never seen any signal from any network on this phone yet with an MTS, AT&T and an old Rogers SIM
EDIT: Actually you will probably have to be on CM9. With stock you cant get to the Network Operator section without a SIM card inserted but in CM9 you can

vincom said:
shouldn't forceclose, redl and try reflashing x2 the rogers radio, wipe/format x3 in cwm b4 going back to stock ics
Click to expand...
Click to collapse
Ok I had enough time to do as you suggested above. Wiped like crazy then went back to stock using the ODIN method and the firmware from sammobile.
Actually I figured it out... it only FCs when I have the AT&T SIM card in and I think thats because AT&T is RAT Locked? If I have no SIM in I can get to all the menus.

k, try to set the freq(play around with it) in that menu w/out sim, then shutdown and install sim b4 restarting, left haptic to click "end" is saving

Got home and went right to work. Almost positive the problem is the radio not working now. I managed to get both SIMs reading without issue but neither will get signal of any sort (even straight after stock reflash). Gonna call it for now until I get a hold of my buddys Rogers SIM.
Thanks so much for all the help, I really appreciate it!

THE AT&T DATA THREAD: The Answer to getting LTE working on your N5

IF YOU HAVE ACCESS TO LTE ON AN AT&T PHONE, YOU DONT HAVE TO DO ANYTHING!!!!!!!!
IF YOU ALREADY HAVE A SIM CARD THAT WILL FIT IN THE N5, YOUR SIM IS LTE CAPABLE AND ALL YOU HAVE TO DO IS GET THE RIGHT DATA PROVISION. YOU DO NOT NEED TO GET A NEW SIM!!!!!!!
This happened when the N4 came out and I came to the rescue far too many times to count...and I've already started to read threads about it so here we go!
You just bought an N5 and are either worried about getting LTE or can't get LTE connectivity on your N5. It's a really big issue with a really simple solution. You need to make sure of a few things.
1. You have a SIM that can receive LTE frequency
2. Your data plan is a LTE provisioned plan
3. Your APNs include an LTE ANP
1 & 2 can be solved at the same time and 3 should solve itself in most cases.
Here's the big issue: AT&T doesn't have a data provision for the N5 (or the N4). Your customer service rep will take the IMEI number from your phone when you ask for a new SIM and it will come back with their basic GSM plan by default. This caused awful data speeds on the N4 and will disallow LTE on the N5 so you need to inform them that this will happen before they go through the process. A nice rep will understand. An unknowledgeable rep will claim there is nothing they can do. Ask to speak to the manager. If none of them can help, take your new LTE capable SIM and walk away.
Now after you leave the store call up customer service and tell them you just got a new *insert LTE capable AT&T device here* and you can't find the IMEI number. Tell them you tried to go into the store and they were unhelpful so you're calling. The person will immediately become helpful and generate an IMEI number. They will provision your data using said serial number and you'll be good to go.
BEFORE inserting your SIM, start up your N5. Go through the setup process that you have to go through and then turn it back off. Plug in your SIM and reboot.
Go to Settings > Wireless & Networks > more > Mobile Networks > Access point Names. In there you should see an AT&T LTE APN and it should be already selected. If not, select it. This should be all you need to do. It really is that simple.
NOTES:
- All SIMs that fit in the N4 and N5 are LTE capable
- Here is what your AT&T APN should look like
- If you have any issues, post and I'll do my best to help
As always, Thanks are appreciated.

So even if the rep in store "can't help" I'll still walk out with the SIM card I need? Also, If I don't have my N5/IMEI in hand when I go in can I still setup a plan and get a SIM card? Thanks for the post!
EDIT: Going in with no phone I don't know rather to tell them I have a N5 coming or try to find a friends that will give me their IMEI that I can give them...

You'll get a SIM card no matter what because those are free...it just won't be provisioned properly unless you get a knowledgeable rep.
Having an IMEI in hand makes life easier; having your N5 will make it way easier. The SIM needs to be activated in the store and they will need an IMEI to activate. Just wait till you get your N5 to go through all this. It won't do anything to help you until you get it.
The IMEI will be on the SIM tray!

spitefulcheerio said:
You'll get a SIM card no matter what because those are free...it just won't be provisioned properly unless you get a knowledgeable rep.
Having an IMEI in hand makes life easier; having your N5 will make it way easier. The SIM needs to be activated in the store and they will need an IMEI to activate. Just wait till you get your N5 to go through all this. It won't do anything to help you until you get it.
The IMEI will be on the SIM tray!
Click to expand...
Click to collapse
Ok, I will wait until Wednesday to go in then...one last thing, if it gets to the point I have to call ATT, when I say I can't find the IMEI won't they just tell me to flip the phone over or look in the settings, etc.. instead of generating one?

No.
They will ask you if there is a barcode / serial thing on the back of your device. You say no. Boom, done.
edit: don't forget to hit the thanks button!

So just going in and asking to exchange your sim for a micro sim isn't enough?

I have a note 3 right now with 4g. I was going to use the same Sim card in the note and put in the N5. Should it work out of the box or do I still have to take it in the store? How will I know that I have a an imei card?
Sent from my SAMSUNG-SM-N900A using Tapatalk

GldRush98 said:
So just going in and asking to exchange your sim for a micro sim isn't enough?
Click to expand...
Click to collapse
No. The SIM must be activated and an IMEI is required to activate.
marcusva79 said:
I have a note 3 right now with 4g. I was going to use the same Sim card in the note and put in the N5. Should it work out of the box or do I still have to take it in the store? How will I know that I have a an imei card?
Sent from my SAMSUNG-SM-N900A using Tapatalk
Click to expand...
Click to collapse
I'll make this even easier!
Do you have a SIM that will fit in the N5? If not, follow my steps. If so, skip ahead to calling AT&T customer support because ALL MICRO SIMS ARE LTE CAPABLE.
What do you mean by an IMEI card? All phones come with an IMEI.

great. AT&T why are you so terrible.

Im sim is in the note 3 rught now. Sending it back to att. Getting the n5 tomorrow. New to the Sim card thing. Coming from sprint. Just had to ask.
Sent from my SAMSUNG-SM-N900A using Tapatalk

Hey guys I'm going to switching to straight talk att am I ordered the lte micro sim from them and plan to activate tomorrow should I expect to jump through hoops to get lte or expect the same issues as att users...not sure this is my first try at prepaid

same things will happen. You'll need to get an LTE data provision but will be unable to using your N5 IMEI

marcusva79 said:
I have a note 3 right now with 4g. I was going to use the same Sim card in the note and put in the N5. Should it work out of the box or do I still have to take it in the store? How will I know that I have a an imei card?
Sent from my SAMSUNG-SM-N900A using Tapatalk
Click to expand...
Click to collapse
If you have 4g on your note 3 it means you already have a LTE data plan. All you need to do is take the sim out of your note 3 and pop it into your n5, no need to call anyone or make an unnecessary trip to the store.

4g =/= LTE in AT&Ts case. 4g can mean HSPA+ 4g!
If you have access to LTE currently YOU DO NOT NEED TO DO ANYTHING.

spitefulcheerio said:
Now after you leave the store call up customer service and tell them you just got a new *insert LTE capable AT&T device here* and you can't find the IMEI number.
Click to expand...
Click to collapse
If you have a device and you can't find the IMEI, just go to the settings and about device to view it.. Wouldn't they ask you to do that?
Look, I know you want to dumb down stuff and give advise but some of it is just incorrect, not dumbed down.

Dial *#06# on any Android smartphone and it'll display the IMEI.

spitefulcheerio said:
Here's the big issue: AT&T doesn't have a data provision for the N5 (or the N4). Your customer service rep will take the IMEI number from your phone when you ask for a new SIM and it will come back with their basic GSM plan by default. This caused awful data speeds on the N4 and will disallow LTE on the N5 so you need to inform them that this will happen before they go through the process. A nice rep will understand. An unknowledgeable rep will claim there is nothing they can do. Ask to speak to the manager. If none of them can help, take your new LTE capable SIM and walk away.
Click to expand...
Click to collapse
It's possible that the reps @ the AT&T Stores in different areas aren't properly keying the IMEI in properly. If at all possible have them SCAN the IMEI barcode on the back of the phone.
I went down to the AT&T store here locally (Bay Area, CA) and the only problem I had in the process was a 30 minute wait to see one of the reps.
I was previously on an unlimited data plan that I've had setup since I got my original iPhone 3G - 5 years ago. NOT an LTE plan by any stretch.
He went in the back and grabbed the sim and started the process of adding it to the account.
He scanned the sim and then scanned my phone -- It CORRECTLY recognized the device as a D820 **AND** automatically updated my data plan to the LTE Unlimited.
The only thing the rep had to do was press confirm a number of times. Not once did he have to manually adjust anything.
We waited about 5 minutes for the sim to activate, slipped it into my N5 and powered it up - Instant LTE service.
So AT&T *does* have the IMEI Registered for the N5 with a corresponding LTE Plan. If someone is trying to key it in and getting an error.. they're likely not typing something correctly.

I'm already using a note 3 on at&t with LTE already enabled on my plan. Also,my note 3 already uses a micro-SIM. I should be good to just swap my SIM into the n5 right? I have written down the default AT&T APN just in case it gets list on the n5.
Sent from my SM-N900T using xda app-developers app

misfit0r said:
It's possible that the reps @ the AT&T Stores in different areas aren't properly keying the IMEI in properly. If at all possible have them SCAN the IMEI barcode on the back of the phone.
I went down to the AT&T store here locally (Bay Area, CA) and the only problem I had in the process was a 30 minute wait to see one of the reps.
I was previously on an unlimited data plan that I've had setup since I got my original iPhone 3G - 5 years ago. NOT an LTE plan by any stretch.
He went in the back and grabbed the sim and started the process of adding it to the account.
He scanned the sim and then scanned my phone -- It CORRECTLY recognized the device as a D820 **AND** automatically updated my data plan to the LTE Unlimited.
The only thing the rep had to do was press confirm a number of times. Not once did he have to manually adjust anything.
We waited about 5 minutes for the sim to activate, slipped it into my N5 and powered it up - Instant LTE service.
So AT&T *does* have the IMEI Registered for the N5 with a corresponding LTE Plan. If someone is trying to key it in and getting an error.. they're likely not typing something correctly.
Click to expand...
Click to collapse
This is good to know, I am going to do this today as my nexus 5 should be arriving sometime today. So have the rep scan and should be good to go, at least I have a game plan if I run into some problems.
Thanks

Great thread. Could you please take a look at my issue with LTE being slower than 3G here? http://forum.xda-developers.com/showthread.php?t=2513844
I've tried adding a new APN but the phone keeps deleting it!
Sent from my Nexus 5 using Tapatalk

[Q] us cellular note 2 to page plus not getting 3g please help

Hello everyone hope you can help me.
I did a full flash using fla****now.com on my us cellular note 2 sch-r950 to page plus and I got talk and txt to work but not 3g. I had gotten a USED Verizon 4g lte sim card which was what I was told would work to get 3g, but since it did not work now I've been asking around and people have told me that since the sim is 4g it is not needed to get 3g. That even w/o a sim card I should be able to get 3g but that the 3g on the phone might not be showing. I have also read that you can get 3g only with a us cellular 4g sim card, so I'm really confused.
The phone says "no sim" with the verizon 4g lte sim card so don't know if it read it I could get 3g if what I was initially told was true.... Another thing is that my old Verizon phone has a different prl than this us cellular note 2 and I am not getting service where I used to get service. Question, if I change the prl to the one that my old phone had would the note 2 give me the same coverage? I had my old phone with page plus too, just did the esn change before it was flashed. And if that would work how do I do it? One last thing does anyone know how to get 3g on this us cellular note 2 sch-r950? I really need the 3g working bc I fill my paperwork online.
Any help will be greatly appreciated. Sorry for the long post but the better explained the better the help no?
Thank you!

data on us cellular note 2
sadjetivo said:
Hello everyone hope you can help me.
I did a full flash using fla****now.com on my us cellular note 2 sch-r950 to page plus and I got talk and txt to work but not 3g. I had gotten a USED Verizon 4g lte sim card which was what I was told would work to get 3g, but since it did not work now I've been asking around and people have told me that since the sim is 4g it is not needed to get 3g. That even w/o a sim card I should be able to get 3g but that the 3g on the phone might not be showing. I have also read that you can get 3g only with a us cellular 4g sim card, so I'm really confused.
The phone says "no sim" with the verizon 4g lte sim card so don't know if it read it I could get 3g if what I was initially told was true.... Another thing is that my old Verizon phone has a different prl than this us cellular note 2 and I am not getting service where I used to get service. Question, if I change the prl to the one that my old phone had would the note 2 give me the same coverage? I had my old phone with page plus too, just did the esn change before it was flashed. And if that would work how do I do it? One last thing does anyone know how to get 3g on this us cellular note 2 sch-r950? I really need the 3g working bc I fill my paperwork online.
Any help will be greatly appreciated. Sorry for the long post but the better explained the better the help no?
Thank you!
Click to expand...
Click to collapse
Did you ever get data working? If not, I think I can help.
First did you put in a micro sim (preferrably not Verizon) t mobile att etc... Also you can root and freeze setup wizard to get rid of the "non Verizon sim card" message. Thirdly if your username and keys are wrong HDR an long, PPP and the ha and AAA usernames and passwords, then you will only have talk and text and no 3g data.
Flashing sim card models is tricky. I believe I can help.
If you already have this done and data working, please share what you did so we can learn from each other and share the knowledge wealth for the whole community. Thanks

Anyone have LTE working on Straight Talk (AT&T Network)

I've had my OnePlus One working great on Straight Talk (AT&T) for a couple weeks now. However, I am using an old SIM card. A lot of people are saying that an "LTE-compatible" SIM card is needed in order to get on LTE. I have ordered a new SIM from Straight Talk and am waiting for it to arrive.
What APN settings are you folks using for LTE? Also, what kind of speeds are you seeing?
Thank you!

martyxng said:
I've had my OnePlus One working great on Straight Talk (AT&T) for a couple weeks now. However, I am using an old SIM card. A lot of people are saying that an "LTE-compatible" SIM card is needed in order to get on LTE. I have ordered a new SIM from Straight Talk and am waiting for it to arrive.
What APN settings are you folks using for LTE? Also, what kind of speeds are you seeing?
Thank you!
Click to expand...
Click to collapse
I am patient waiting for the mail to get here today with my OPO.
I stopped by Wally World yesterday, and got a SIM. I am going to be switching from Verizon, so I will let you know how everything goes.

You need an LTE capable SIM. I'm on ATT and LTE works fine, but the IMEI's of the OPO are not LTE ready in ATT's database, so just give them the IMEI of another LTE capable phone that you own and you'll be fine.

Chris123NT said:
I'm on ATT and LTE works fine, but the IMEI's of the OPO are not LTE ready in ATT's database, so just give them the IMEI of another LTE capable phone that you own and you'll be fine.
Click to expand...
Click to collapse
That stinks - I don't have another LTE capable phone. Hopefully they'll get them set up with AT&T soon. I'm not clear from your post if you are on Straight Talk AT&T or directly on AT&T. If Straight Talk, which APN settings did you go with?

martyxng said:
That stinks - I don't have another LTE capable phone. Hopefully they'll get them set up with AT&T soon. I'm not clear from your post if you are on Straight Talk AT&T or directly on AT&T. If Straight Talk, which APN settings did you go with?
Click to expand...
Click to collapse
AT&T direct, but the straight talk APN's are built into CM so you shouldn't have to do anything to get LTE. Not sure if ST uses the same registration process where you have to give them your IMEI etc... But see what happens when you get your SIM.

Chris123NT said:
AT&T direct, but the straight talk APN's are built into CM so you shouldn't have to do anything to get LTE. Not sure if ST uses the same registration process where you have to give them your IMEI etc... But see what happens when you get your SIM.
Click to expand...
Click to collapse
I just received the SIM card and transferred my service to it on the Straight Talk website. The site gave these settings, which match the "StraightTalk ATT" settings built into CyanogenMod:
APN Name: Straight Talk
APN: tfdata
Port: 80
MMSC: http://mms-tf.net
MMS Proxy: mms3.tracfone.com
MMS Port: 80
I saw the H+ logo as I did before, and I was getting 3-6Mbps download as I was with the prior SIM card. I looked 10 minutes later, and there was a 4G icon there. I now get 8-16Mbps. Much better!

I was able to port my number from Verizon this afternoon and use the "StraightTalk ATT" APN.
I am getting about 20 Mbps down and 7 up.

New SIM
I'm on ST. My old sim, that worked in my galaxy note (GT-N7000), which didn't have LTE, I popped into my Huawei Ascend Mate2, after shaving it down to fit. H+, no LTE. Went online, ordered a new LTE microsim from ST, came about 4 days later. Card had a new IMEI number to use
not the one in the phone. Activated it, instructions said leave the old one in the phone til the signal disappeared. Took about 30 minutes, signal dropped, popped the new one in, threw in the APN settings from the card, rebooted and the LTE popped right up.
Card was less than 10 dollars, delivered.

Chris123NT said:
AT&T direct, but the straight talk APN's are built into CM so you shouldn't have to do anything to get LTE.
Click to expand...
Click to collapse
That explains all the APN entries in addition to the ones I'd set up with my Nexus 5.
When I went from my Nexus 4 to Nexus 5 last November, I had to buy a new SIM ($7) to get LTE, but after that it was fine. Straight Talk AT&T in metro Detroit area.
Posted from my 1+ One via Tapatalk.

Strangely, I have an AT&T SIM (Through Straight Talk), and I get LTE speeds on my Galaxy S3. Put it into my OnePlus One (with the same APN settings, and it only shows up as H+. I ordered a new SIM to see if that does the trick, but I'm finding the whole thing to be a bit baffling.

joeonetime said:
Strangely, I have an AT&T SIM (Through Straight Talk), and I get LTE speeds on my Galaxy S3. Put it into my OnePlus One (with the same APN settings, and it only shows up as H+. I ordered a new SIM to see if that does the trick, but I'm finding the whole thing to be a bit baffling.
Click to expand...
Click to collapse
Since you already have a sim that is working on LTE, you dont actually need a new sim card... All you had to do was call Atnt and give tell them that you got a new phone and it is one plus one......they will then register your new phone on the network and you would be able to get LTE on the one using your old sim.......try it!!!

CyanogenMod 12.1 - D850 - No LTE

I seem unable to get LTE on my D850 since I installed CM12.1 and was wondering if this is common for this ROM. I installed the nightly, so I assume its obviously going to be a bit buggy, but to not have LTE working seems strange.
I checked my APN and I tried both ATT LTE and ATT Phone. The ATT LTE gives me a status bar with an exclamation point and never establishes a data connection and ATT Phone gives me HSPA connectivity. At one time, I waited a few hours and it eventually established LTE but that was an uncommon occurrence and its never been repeated since.
With other ROMs I have not seen this issue replicated. I tested on Cyanide L, Euphoria, and the Stock LG ROM and everything worked fine. Any suggestions?

Hey there,
I'm running CyanideL myself, love this ROM.
Which nightly version are you using?
Have you checked that Mobile Networks --> Preferred network type.... is set to LTE?
Have you tried toggling to 3G, getting a connection, then moving back to LTE?

I also have this problem. Has a solution been found?
I just ditched the stock ROM and installed CM12.1 a few days ago. Now LTE has disappeared. I had it, now can't get it. I'm not able to select LTE in the settings→Mobile networks→Preferred network type menu, nor can I select any option that includes LTE in the test menu (*#*#4636#*#*). It's probably some stupid user error, but whatever it is has been eluding me for a day of messing with it.
Presently running cm-12.1-20150804-NIGHTLY-d850.

wseverin said:
I also have this problem. Has a solution been found?
I just ditched the stock ROM and installed CM12.1 a few days ago. Now LTE has disappeared. I had it, now can't get it. I'm not able to select LTE in the settings→Mobile networks→Preferred network type menu, nor can I select any option that includes LTE in the test menu (*#*#4636#*#*). It's probably some stupid user error, but whatever it is has been eluding me for a day of messing with it.
Presently running cm-12.1-20150804-NIGHTLY-d850.
Click to expand...
Click to collapse
Interesting...
Have you tried restoring your stock ROM and seeing if it will connect? How about a SIM card pull?

Have you tried restoring your stock ROM and seeing if it will connect? How about a SIM card pull?
Click to expand...
Click to collapse
Thanks for the reply. I have not tried returning to the stock ROM. I just got all my apps reinstalled and data restored, widgets installed, screens set up, etc., so I'm not too keen on doing all that again so soon.
I have tried a chicken SIM card pull. I was somewhat fearful of doing a pull "hot" as is usually suggested. I powered down, removed the SIM card, and restarted. After restart, I was able to select LTE in the settings→Mobile networks→Preferred network type menu, and the test menu confirmed that LTE/GSM auto was the preferred network type.
I then powered down, re-installed the SIM, and restarted. After restart the preferred network type had been reset to 3G and I was (am) unable to select LTE.
My conclusion is that this is something to do with the Net10 SIM I'm using. I've ordered a new SIM from Net10. The Net10 rep says a new SIM may fix things. One is on it's way and should be here in a few days. I'll post the result.

[SOLVED]
My new "LTE capable" Net10 SIM arrived today. I had Net10 customer service transfer my service to the new SIM. Now I have LTE; I'm able to select LTE in the Settings→Mobile_Networks→Preferred_Network_Type menu, LTE appears in the CM12.1 status bar, and I'm able to make a solid LTE connection.
I will here piece together everything I've learned from my own experience, Net10 customer support, and internet searching. My conclusion is that there are TWO compounding problems for Tracfone/Net10/StraightTalk users. One is techhnical and the other is marketing.
The technical issue is that all Net10 (also Tracfone and Straight Talk) AT&T SIMs sold up to a couple of months ago don't work with LTE on the AT&T network. That's most of the AT&T SIMs from these companies out there in the world today. This is not widely known – in fact, most of the Net10/TF/ST customer service reps are not aware of it. It's not something that Tracfone and its subsidiaries want known because it would cost them a bundle replacing SIM cards for unhappy customers. If you have a Net10/TF/ST SIM that's more than a few months old, you have to call Net10/TF/ST and buy another new one that's compatible with AT&T LTE if you want LTE service.
So, why don't more Net10/TF/ST AT&T users raise a fuss and demand LTE capable SIMs? That brings us to the marketing issue.
AT&T lies. So do Tracfone and its subsidiaries. AT&T markets its HSPA+ 3G service as 4G when it's not. In fact, the AT&T stock ROMs that most people are using lie. The stock ROMs display 4G or sometimes 4GLTE (depending on ROM version) in the status bar when in fact it's a HSPA+ connection; not 4G let alone LTE. So users cruise along using their old SIM cards happily thinking they have 4G or LTE connections when in fact they do not; and they're none the wiser. It's only more sophisticated users who flash a 3rd party ROM, one that doesn't lie, who figure it out.
(solution cross posted to similar thread at http://forum.cyanogenmod.org/topic/113404-cant-select-preferred-network-type-lte/)