I figure this is a development question but if this needs to be moved feel free to do so mods. I compiled AOSP GB no problem but now it's bootlooping whenever I try to start it up. It doesn't even get past the first boot screen so ADB isn't even available. I thought it might be a kernel issue but I tried the CM7 kernel, stock kernel and stock GB kernel. No avail. I compiled GB for the Evo no problem before but it's not working now. Any ideas?
chuckhriczko said:
I figure this is a development question but if this needs to be moved feel free to do so mods. I compiled AOSP GB no problem but now it's bootlooping whenever I try to start it up. It doesn't even get past the first boot screen so ADB isn't even available. I thought it might be a kernel issue but I tried the CM7 kernel, stock kernel and stock GB kernel. No avail. I compiled GB for the Evo no problem before but it's not working now. Any ideas?
Click to expand...
Click to collapse
You have been around dd for awhile, so I will not ask if you did a full wipe before you flashed the ASOP GB (faux?).
But if you have tried flashing all those other ROM' it may be time to do it again. Also, after flashing an Ext4 kernel, you will generally not be able to flash successfully any of the Ext3 kernel ROM's you mentioned above. You would have to restore an Ext3 nandroid first
You did not say if you had a nandroid on you SD. If not, you may have to put one on - the only one I know of is on a thread in the development section. But this will take you back to square one - unless you had an app backup program on the SD like titanium.
gaww said:
You have been around dd for awhile, so I will not ask if you did a full wipe before you flashed the ASOP GB (faux?).
But if you have tried flashing all those other ROM' it may be time to do it again. Also, after flashing an Ext4 kernel, you will generally not be able to flash successfully any of the Ext3 kernel ROM's you mentioned above. You would have to restore an Ext3 nandroid first
You did not say if you had a nandroid on you SD. If not, you may have to put one on - the only one I know of is on a thread in the development section. But this will take you back to square one - unless you had an app backup program on the SD like titanium.
Click to expand...
Click to collapse
Yeah I had a nandroid and everything. I'm thinking it has to be a kernel thing so I'm going to try a nandroid backup to the stock rom and then see if flashing works. I'll keep ya'll updated. Thanks.
I flashed Jelly Bean unofficial CM10. For some reason, I feel it is slow in response, and I want to go back to Gingerbread. When I flash GB ROM (Zeus 6), It just boot loops.
Am I missing something? Or Do I have to go to ODIN stock before flashing GB?
Any help
You can try flashing a gb kernel in cwm.
Wipes and Format the usual
Go to voodoo, make sure voodoo conversion and lagfix is on.
Reboot into cwm
Reflash gb rom
qkster said:
You can try flashing a gb kernel in cwm.
Wipes and Format the usual
Go to voodoo, make sure voodoo conversion and lagfix is on.
Reboot into cwm
Reflash gb rom
Click to expand...
Click to collapse
At this point, I am stuck @ boot loop How do I get GB kernel to flash in CWM?
paluinfusion said:
At this point, I am stuck @ boot loop How do I get GB kernel to flash in CWM?
Click to expand...
Click to collapse
the kernel can be flashed in recovery or in download mode.
start here if you don't know what I'm talking about.
http://forum.xda-developers.com/showthread.php?t=1437548
You have to Odin or heimdal back...you need something with a working pit...problem is there is no conversion for going back through any cwm zips...so Odin or heimdal is the only way back
Cm10 is in mtd format...no gingerbread or ics Rom is in mtd format
Sent from my HTC Holiday using Tapatalk 2
mg2195 said:
You have to Odin or heimdal back...you need something with a working pit...problem is there is no conversion for going back through any cwm zips...so Odin or heimdal is the only way back
Cm10 is in mtd format...no gingerbread or ics Rom is in mtd format
Sent from my HTC Holiday using Tapatalk 2
Click to expand...
Click to collapse
yup, aosp re-purposes some samsung partitions. the needed data for touchwiz roms is gone. need a full pit flash with preferably all the partitions, might have to take param.ifs, cache, and/or dbdata from a froyo rom. can't remember atm what came in the gb updates but it wasn't everything.
Dani897 said:
yup, aosp re-purposes some samsung partitions. the needed data for touchwiz roms is gone. need a full pit flash with preferably all the partitions, might have to take param.ifs, cache, and/or dbdata from a froyo rom. can't remember atm what came in the gb updates but it wasn't everything.
Click to expand...
Click to collapse
Has anyone successfully gone back to ICS or GB from JB? I dont want to mess up my phone any more than it is.
Dani897 said:
yup, aosp re-purposes some samsung partitions. the needed data for touchwiz roms is gone. need a full pit flash with preferably all the partitions, might have to take param.ifs, cache, and/or dbdata from a froyo rom. can't remember atm what came in the gb updates but it wasn't everything.
Click to expand...
Click to collapse
I was hoping that a gb kernel flash (entropy or zen + others) will auto voodoo a non voodoo file system. The first flash will convert the file system. The second flash will install the firmware.
Sort of like a reverse cm7, cm9 or miui that uses mtd.
as for the successful return from cm10, when in doubt, odin or heimdall back to stock with a repartition should get you back to the starting point.
Dani897 said:
yup, aosp re-purposes some samsung partitions. the needed data for touchwiz roms is gone. need a full pit flash with preferably all the partitions, might have to take param.ifs, cache, and/or dbdata from a froyo rom. can't remember atm what came in the gb updates but it wasn't everything.
Click to expand...
Click to collapse
It's not that aosp uses partions differntly..its that the new jb is in mtd which is A whole new file system format with different partions completely...with any ics or older jb Rom i could go back to gb with one simple flash
I think what you meant was this: mtd uses partions differently requiring a full pit flash to go back
madpb said:
Has anyone successfully gone back to ICS or GB from JB? I dont want to mess up my phone any more than it is.
Click to expand...
Click to collapse
With the older jb roms (prior to mtd) I could.go back with a simple flash...with usual wipes of course...after mtd builds I've always heimdaled back using qkster uclb3 one click...thanks qkster
qkster said:
I was hoping that a gb kernel flash (entropy or zen + others) will auto voodoo a non voodoo file system. The first flash will convert the file system. The second flash will install the firmware.
Sort of like a reverse cm7, cm9 or miui that uses mtd.
as for the successful return from cm10, when in doubt, odin or heimdall back to stock with a repartition should get you back to the starting point.
Click to expand...
Click to collapse
Never thought of that...seems possible...ill give it a try when I get home tonight (referring to the voodoo system)
Sent from my HTC Holiday using Tapatalk 2
Originally Posted by madpb
Has anyone successfully gone back to ICS or GB from JB? I dont want to mess up my phone any more than it is.
Click to expand...
Click to collapse
I've also become a big fan of qkster's UCLB3 Heimdall 1-click when it comes time to revert from 4.x.x to 2.3.x. I Heimdall back to stock UCLB3, then Heimdall Zen's A16 OC kernel/CWM combo, and finally boot into CWM Red and restore whatever compatible GB backup I want. I've long since gotten into the habit of keeping several backups stored on internal memory. I got sick of noobing it up and ending up with bootloops. This method's been good to me so far, and I'm sticking with it.
Hi,
I have followed everything in this thread http://forum.xda-developers.com/showthread.php?t=1837863
I have backups nandroid ready and wasn't too sure, if I dont like this build then i could restore back to stock using CWM? or Odin.
I felt that I need to wait for reply to comfirm before flashing this cyanogenMOD 10.
Thanks!
LeonKnight12 said:
Hi,
I have followed everything in this thread http://forum.xda-developers.com/showthread.php?t=1837863
I have backups nandroid ready and wasn't too sure, if I dont like this build then i could restore back to stock using CWM? or Odin.
I felt that I need to wait for reply to comfirm before flashing this cyanogenMOD 10.
Thanks!
Click to expand...
Click to collapse
IF my memory serves me right, with an unlocked bootloader, you can recover to a TW rom but I think its needs to either have the kernel built into it OR you need to somehow flash to a TW kernel. I say this because I think that if your kernel is still an AOSP one, then the device will not boot up.
some roms already come with a kernel for their rom so I think in most cases, with CWM 6.0.1.x, you could restore a TW nandroid.
If you want to restore a backup of a TouchWiz rom you have then just use the EZ Recovery app to flash the hybrid (CWM/Kexec) recovery...reboot to recovery and restore your nandroid. Simple process!
Once the Dev's building TW roms start using the non-kexec flashing method then you will be able to restore using the normal CWM recovery. Just like you said, you can also use ODIN to restore to stock but it's a pain because you have to root all over again. Just know you have a few options.
Ok thanks everyone!
So good
Fwiw... I've been switching back and forth between Synergy and CM for a couple days now (flashing multiple times) and cwm touch works for synergy but u need new cwm for CM10.
Hope this helps.
If im on an ics rom and have a backup of a gingerbread bml rom can I go back to it by simply restoring it in clockwork mod recovery or do I still have to 1 click first? It would be very useful to quickly switch between roms for when I need the better GPS or wifi calling
From the wiki:
MTD ROMs utilize a different partition layout from the stock-based BML ROMs. Because of this, BML Nandroid backups will not work with MTD based ROMs, and vice versa. Also, once you have flashed an MTD ROM, you must go back to stock first before installing another BML ROM. There are also a number of other differences present in MTD ROMs. MTD ROMs require the Google (Nexus S) USB drivers as opposed to the Samsung USB drivers.
Click to expand...
Click to collapse
It would be cool if we got something like this working sometime in the future, for these situations.
No....have to one click back unfortunately
http://forum.xda-developers.com/showthread.php?t=1470716
download One click Heimdall, it will revert your phone back to stock 2.3.6, its pretty easy if you follow the guide:fingers-crossed:
My Samsung Galaxy S 4G is going through some pretty awesome times in its life right now. However, I'm worried that flashing/restoring the wrong way is going to cut its winning streak short. I mainly stick to the Cyanogenmods found here. ClockworkMod will be abbreviated as CWM, Cyanogenmod as CM. Below is the full history of this device in chronological order:
>Samsung Stock KJ6 (Gingerbread 2.3.6, BML)
>Root w/SuperOneClick
>Bhundven's Subtly Modified Stock with CWM5 + Voodoo Lagfix (kernel w/CWM5.0.2.7)
>Valhalla Black Edition (Gingerbread, BML, CWM5, bhundven's KJ6 Beta2 kernel)
>Cyanogenmod 7.2 (Gingerbread, MTD, CWM5.0.2.8, cyanogenmod-GB kernel)
>Cyanogenmod 9 (Ice Cream Sandwich, MTD, CWM6.0.1.0, 2.6.35.7-cyanogenmod-ICS kernel w/Hefe Kernel changes)
>Cyanogenmod 10 (Jellybean 4.1.x, MTD, CWM6.0.1.9, 2.6.35.7-cyanogenmod-JB Proton kernel)
>Cyanogenmod 9 (Ice Cream Sandwich, MTD, CWM6.0.1.0, 2.6.35.7-cyanogenmod-ICS kernel w/Hefe Kernel changes)
>Cyanogenmod 10.1 (Jellybean 4.2.2, MTD, CWM6.0.3.2, Aries 3.0.84 kernel)
After flashing CM10, I got caught in a bootloop (a confirmed bug in the ROM), and I had to use CWM to restore a CM9 nandroid/backup. I then flashed to CM10.1, and this is where I'm currently at. However, I want to go back to CM9 once again, the GPS only works on the ICS ROMs.
Can I restore CM9 using my current version CWM, or does the recovery version have to be the exact same build? I didn't seem to have any problems restoring CM9 from CM10, and I'm still not sure if there were any consequences in doing that.
From what I've read, restoring has to be done on the same Recovery version as the Nandroid. I've watched many Youtube videos of people suggesting that they flash ROMs on "a daily basis", I'm trying to figure out how they are comfortable with this, given such a restrictive restore environment.
Double44 said:
My Samsung Galaxy S 4G is going through some pretty awesome times in its life right now. However, I'm worried that flashing/restoring the wrong way is going to cut its winning streak short. I am only running unofficial Cyanogenmods found here. ClockworkMod will be abbreviated as CWM, Cyanogenmod as CM. Below is the full history of this device in chronological order:
>Samsung Stock KJ6 (Gingerbread 2.3.6, BML)
>Root w/SuperOneClick
>Bhundven's Subtly Modified Stock with CWM5 + Voodoo Lagfix (kernel w/CWM5.0.2.7)
>Valhalla Black Edition (Gingerbread, BML, CWM5, bhundven's KJ6 Beta2 kernel)
>Cyanogenmod 7.2 (Gingerbread, MTD, CWM5.0.2.8, cyanogenmod-GB kernel)
>Cyanogenmod 9 (Ice Cream Sandwich, MTD, CWM6.0.1.0, 2.6.35.7-cyanogenmod-ICS kernel w/Hefe Kernel changes)
>Cyanogenmod 10 (Jellybean 4.1.x, MTD, CWM6.0.1.9, 2.6.35.7-cyanogenmod-JB Proton kernel)
>Cyanogenmod 9 (Ice Cream Sandwich, MTD, CWM6.0.1.0, 2.6.35.7-cyanogenmod-ICS kernel w/Hefe Kernel changes)
>Cyanogenmod 10.1 (Jellybean 4.2.2, MTD, CWM6.0.3.2, Aries 3.0.84 kernel)
After flashing CM10, I got caught in a bootloop (a confirmed bug in the ROM), and I had to use CWM to restore a CM9 nandroid/backup. I then flashed to CM10.1, and this is where I'm currently at. However, I want to go back to CM9 once again, the GPS only works on the ICS ROMs.
Can I restore CM9 using my current version CWM, or does the recovery version have to be the exact same build? I didn't seem to have any problems restoring CM9 from CM10, and I'm still not sure if there were any consequences in doing that.
From what I've read, restoring has to be done on the same Recovery version as the Nandroid. I've watched many Youtube videos of people suggesting that they flash ROMs on "a daily basis", I'm trying to figure out how they are comfortable with this, given such a restrictive restore environment.
Click to expand...
Click to collapse
I think that you'll just need to be on one recovery at all times. I don't recommend updating your recovery.
Smack that thanks button If I helped!
Always make a nandroid backup before trying anything risky
Sent from my fabulous N7105 powered by Illusion ROM and Plasma Kernel.
Sent from dat small country called Singapore.
P.S. Quote my post for replies ASAP.
Thanks for the quick response
I'm not sure how it's possible to stick with one recovery? A new recovery version comes with each ROM I flash on the T959V, it's impossible to keep recovery the same.
Double44 said:
Thanks for the quick response
I'm not sure how it's possible to stick with one recovery? A new recovery version comes with each ROM I flash on the T959V, it's impossible to keep recovery the same.
Click to expand...
Click to collapse
Keep the recovery file in your sd-card. Flash it everytime u flash a new rom. (Make sure the rom you're using is compatible with that recovery though)
Smack that thanks button If I helped!
Always make a nandroid backup before trying anything risky
Sent from my fabulous N7105 powered by Illusion ROM and Plasma Kernel.
Sent from dat small country called Singapore.
P.S. Quote my post for replies ASAP.
Short answer, "I just flash with whatever recovery I have on my phone. In the rare cases that doesn't work, I flash a different recovery manually."
Long answer:
On the SGS4G, it is non-trivial to keep the recovery as it is integral with the run-time boot image. Flash a kernel, you flash recovery as well. You almost always get the kernel in a ROM.
Within a given Android release, you should be able to use "any" recovery to flash any well-built ROM. I regularly flash TWRP-based ROMs using CWR and vice versa.
I haven't looked into getting CWR to recognize a TWRP backup or vice versa though. They should both hold the same information, but I don't know how well they "play with others" on their naming, locations, and formats.
There sometimes are differences in how the ROM's "install me" code runs in different Android versions and occasionally, for example, a JB-era recovery won't flash a GB-era ROM or vice versa. When that happens, you can generally flash a kernel of the "target" ROM by itself, then flash the rest of the ROM. It is pretty easy if you have a Mac or Linux machine, a bit more complicated if you're running Windows. Making cross-version upgrades reliable are one of the more challenging things a custom-ROM maker needs to deal with.
You generally don't want to try to mix a /data partition from one Android version with a /system from another. Some of the user-space backup utilities like Titanium Backup can do a decent job of upgrading data from one Android version to another. I've never tried to downgrade.
jeffsf said:
Short answer, "I just flash with whatever recovery I have on my phone. In the rare cases that doesn't work, I flash a different recovery manually."
Long answer:
On the SGS4G, it is non-trivial to keep the recovery as it is integral with the run-time boot image. Flash a kernel, you flash recovery as well. You almost always get the kernel in a ROM.
Within a given Android release, you should be able to use "any" recovery to flash any well-built ROM. I regularly flash TWRP-based ROMs using CWR and vice versa.
I haven't looked into getting CWR to recognize a TWRP backup or vice versa though. They should both hold the same information, but I don't know how well they "play with others" on their naming, locations, and formats.
There sometimes are differences in how the ROM's "install me" code runs in different Android versions and occasionally, for example, a JB-era recovery won't flash a GB-era ROM or vice versa. When that happens, you can generally flash a kernel of the "target" ROM by itself, then flash the rest of the ROM. It is pretty easy if you have a Mac or Linux machine, a bit more complicated if you're running Windows. Making cross-version upgrades reliable are one of the more challenging things a custom-ROM maker needs to deal with.
You generally don't want to try to mix a /data partition from one Android version with a /system from another. Some of the user-space backup utilities like Titanium Backup can do a decent job of upgrading data from one Android version to another. I've never tried to downgrade.
Click to expand...
Click to collapse
Twrp backups won't work with cwm and vice versa. I've tried it.
Smack that thanks button If I helped!
Always make a nandroid backup before trying anything risky
Sent from my fabulous N7105 powered by Illusion ROM and Plasma Kernel.
Sent from dat small country called Singapore.
P.S. Quote my post for replies ASAP.
I feel like a more simple way is to go back to stock, re-root, and then go back to CM9.
I'm suddenly bursting at the seams with questions.
Irwenzhao said:
Keep the recovery file in your sd-card. Flash it everytime u flash a new rom. (Make sure the rom you're using is compatible with that recovery though)
Click to expand...
Click to collapse
Where would I look to find ROM/recovery compatibility? If I'm not mistaken, none of the ROMs I've used go into these details.
How would I backup a recovery? I would use ROM Manager, but ROM Manager is not compatible with the SGS4G. I've been doing my work manually through CWM only (which is recommended anyway), and I don't think CWM can be backed up through CWM itself.
I am planning to restore a CM9 backup eventually. If I were to backup a recovery, would I backup the current Jellybean recovery I have (CWM6.0.3.2), or would I be better off to backup the recovery that comes with the CM9/ICS nandroid (CWM6.0.1.0)? Both CWM's have software version 6, which almost makes sense that I was able to restore from CM10 before (CWM6.0.1.9); the only differences between the two recoveries are their build numbers.
If I were in need of a specific SGS4G kernel, where would a person look? I may need the kernel to CM9 (2.6.35.7-cyanogenmod-ICS kernel w/Hefe Kernel changes). Now that I think about it, what's the most important factor when restoring, the kernel or the version of recovery?
jeffsf said:
Short answer, "I just flash with whatever recovery I have on my phone. In the rare cases that doesn't work, I flash a different recovery manually."
Long answer:
On the SGS4G, it is non-trivial to keep the recovery as it is integral with the run-time boot image. Flash a kernel, you flash recovery as well. You almost always get the kernel in a ROM.
Within a given Android release, you should be able to use "any" recovery to flash any well-built ROM. I regularly flash TWRP-based ROMs using CWR and vice versa.
I haven't looked into getting CWP to recognize a TWRP backup or vice versa though. They should both hold the same information, but I don't know how well they "play with others" on their naming, locations, and formats.
There sometimes are differences in how the ROM's "install me" code runs in different Android versions and occasionally, for example, a JB-era recovery won't flash a GB-era ROM or vice versa. When that happens, you can generally flash a kernel of the "target" ROM by itself, then flash the rest of the ROM. It is pretty easy if you have a Mac or Linux machine, a bit more complicated if you're running Windows. Making cross-version upgrades reliable are one of the more challenging things a custom-ROM maker needs to deal with.
You generally don't want to try to mix a /data partition from one Android version with a /system from another. Some of the user-space backup utilities like Titanium Backup can do a decent job of upgrading data from one Android version to another. I've never tried to downgrade.
Click to expand...
Click to collapse
How would you manually flash a different recovery if you've already wiped the device? Are you restoring the current ROM, then downloading a different kernel, and trying again?
You wouldn't want to flash a BML ROM with an MTD ROM's recovery. You may know this already, but there are Gingerbread ROMs with both BML & MTD layouts. Luckily this trend disappears on the ICS ROMs by keeping it MTD, I don't plan on flashing any lower than ICS because of this.
Regarding your last sentence, isn't this why a person would wipe data and format /system before flashing?
AnAznBoy9724 said:
I feel like a more simple way is to go back to stock, re-root, and then go back to CM9.
Click to expand...
Click to collapse
I may not need to go down that route just yet.. though I could be wrong.
Double44 said:
I'm suddenly bursting at the seams with questions.
Where would I look to find ROM/recovery compatibility? If I'm not mistaken, none of the ROMs I've used go into these details.
Click to expand...
Click to collapse
Most ROM builders seem to be happy about just getting their ROM to flash over common other ROMs in use for the phone when they release them. It's more a case of "I tried it and it didn't work" for most ROMs. Clear exceptions include at least:
Froyo and Gingerbread had different boot loaders
Some MTD ROMs can't be flashed from a BML kernel
I don't know of any BML ROM that can be flashed from an MTD kernel
SELinux throws a wrench into cross-kernel flash compatibility
How would I backup a recovery? I would use ROM Manager, but ROM Manager is not compatible with the SGS4G. I've been doing my work manually through CWM only (which is recommended anyway), and I don't think CWM can be backed up through CWM itself.
Click to expand...
Click to collapse
/mnt/sdcard/TWRP or /mnt/sdcard/Clockwork have the backups in them. If you look at them in detail (and ignore the suffix) /data and /system and your android-secure are generally something manageable like tar or cpio format. Titanium Backup (Pro, at least) can read both CWR and TWRP backups.
I am planning to restore a CM9 backup eventually. If I were to backup a recovery, would I backup the current Jellybean recovery I have (CWM6.0.3.2), or would I be better off to backup the recovery that comes with the CM9/ICS nandroid (CWM6.0.1.0)? Both CWM's have software version 6, which almost makes sense that I was able to restore from CM10 before (CWM6.0.1.9); the only differences between the two recoveries are their build numbers.
Click to expand...
Click to collapse
You backup "recovery" every time you backup boot on the SGS4G. The recovery partition, as I understand the early bootloaders, is never used. It is the same image in both partition.
If I were in need of a specific SGS4G kernel, where would a person look? I may need the kernel to CM9 (2.6.35.7-cyanogenmod-ICS kernel w/Hefe Kernel changes). Now that I think about it, what's the most important factor when restoring, the kernel or the version of recovery?
Click to expand...
Click to collapse
If you wanted just the boot image from a ROM installer, which includes both the kernel and recovery, pretty much inseparably bound together, then you can un-zip the ROM and look for boot.img in the extracted files. It should also be the contents your "nandroid" backup of the boot or recovery partition (though I haven't confirmed that it is bit-for-bit equivalent, I would be surprised if it wasn't). You can grab the current Hefe Kernel which is what I generally use as my "go to" kernel for ICS. Then again, I'm arguably biased.
How would you manually flash a different recovery if you've already wiped the device? Are you restoring the current ROM, then downloading a different kernel, and trying again?
Click to expand...
Click to collapse
heimdall is your friend, along with a "recovery jig" or "download jig" (under $5 to make, or off eBay). You can flash a soft-bricked device with it.
Code:
heimdall flash --KERNEL path/to/boot.img
@bhundven thinks that 1.3.1 is the latest you should use.
http://forum.xda-developers.com/showthread.php?t=755265
http://glassechidna.com.au/heimdall/
https://github.com/Benjamin-Dobell/Heimdall/downloads
It can also be done from the command line, for example using adb into recovery. As a mis-typed command using that approach could potentially blow away boot loaders or the like, I tend not to use it myself.
You wouldn't want to flash a BML ROM with an MTD ROM's recovery. You may know this already, but there are Gingerbread ROMs with both BML & MTD layouts. Luckily this trend disappears on the ICS ROMs by keeping it MTD, I don't plan on flashing any lower than ICS because of this.
Click to expand...
Click to collapse
You can always use one of the one-click installers to get back to GB, if you want or need. I tend to be slow to upgrade as you can't reliably go back with your data, even with backups.
Regarding your last sentence, isn't this why a person would wipe data and format /system before flashing?
Click to expand...
Click to collapse
A ROM shouldn't care what's on /data though some are apparently unhappy with the cruft of others. Other have not been as lucky as I seem to have been. I always back up before flashing, and immediately go back if it didn't seem to go right, before I put in my SIM or turn on WiFi. (I always try to remember to turn off WiFi and pull my SIM card so that I don't have important changes in my app data when changing ROMs.)
I guess how many ROMs a day you are flashing, how likely you think it is that the ROM is "functional" and how easily you can recover from a bad one impacts how you make your personal decision about what your process is.
On the other hand, if you are changing Android versions, yes, wipe, clean install, and carefully restore app data, with frequent backups so you don't have to start over if something goes wrong.