[HD2 Android NAND Development] AngelDeath:
Okay let me try to narrow somethings down from what I read, and maybe this might shed some light on some people being confused.

The Bad blocks are a problem, and the causes can be anything, be it, too many flashes, possible incorrect writing, Voltage (UC or OC), taking the battery out when its locked up, the list can go on, but I dont think kernels are the cause of bad blocks personally. One of the best ways to know if you have bad blocks is to run mtty, doing a flash and looking at the recovery isnt the best way.

Also as most have seen partition sizing does make a difference. To recap, I have 2 HD2's one with no bad blocks, the other with several. When I was making roms for the HD2 I would test it on both HD2s, and it was a sense rom. The key here is the test phone it would run perfect on, but on my daily use phone had all kind of errors, nothing was different at all, after batting my head for 3 days during rom testing I decided to use mtty and see what was going on, there is where I found that I had bad blocks, so I checked the test phone that the rom was working perfectly, no bad blocks. And both had more then 100MB of free space after first boot, and 120MB of free memory. When I took the bad block phone and reduced the partition sizes and used the Eu version of my rom all the problems disappeared instantly. And since then I have switched to ZFreaks Sense 3.5 rom, using the EU version, I have had no issues (I tested his tmobile version and encountered the same issues as I did in my own rom).

What is the cause of the bad blocks, unknown the list can be anything as I listed above. One thing I do know is this, IF you installed a rom that was working without any major problems, and reflashing it causes problems all of sudden, format the partitions and re-do your flash. If it happens again, then check with mtty if you have bad blocks.

Do not try beta roms, or roms that do have problems and then think its bad blocks, because I have seen in the thread some people posting there logs with no errors but yet cant install the rom. If its not stable and you see others having trouble expect you will to. If you dont see bad blocks in your info, the likely hood that rom troubles are possibly something else.

WM doesnt seem to experience this as great as Android, partly because I believe what I have started in the beginning of this thread, during flashing there is no error checking being done correctly. In windows mobile, I believe during either the wiping that happens or during boot up, there must be some sort of FAT and bad sector list that is making sure that files do not get written to that location. I feel that since our HD2's were made for windows Mobile, this is lacking during the two areas.

Until we have some sort of error checking routine or a bad sector file, I dont think this problem will fix itself. Understand that this bad sector file also would have to be maintained during installs of 3rd party apps, because if the rom after being flashed isnt being written to the bad block, a install of an app just might. This is where ext4 I think makes the difference at least in the HD2. but until ext4 (which I doubt will happen at this stage) this will trouble the HD2.

Running Android from an SDcard will avoid the bad block issue since it is running on your SDcard and not on the actual phone but this has some dis-advantages as well, if you happen to have issues during this type of setup, then it clearly isnt the nand thats causing the issue but another hardware issue, ex: phone hardware, or SDCard failure.

One other thing to also pay attention to, which I believe makes a difference, Board Revisions. We have seen this with revisions of the touch screen, when it comes back from repair alot are complaining that the screen doesnt work in android but works fine in Windows Mobile, this is because of a driver issue, and this was also established quite some time ago. I believe this to be the case as well with new motherboards being put into phones being fixed. As you can see when some of you are getting back your HD2 from repair, the new motherboard has errors, this solidifies my thought that its irrelevant when using the phone with Windows Mobile, Because if further confirms my thought that the file allocation table and bad sector list will prevent writing to that location.

Hope this helps some of the people that were/are confused about this whole process. But I feel that since the HD2 has become quite old at this point any major changes on how the file system is being utilized currently will not change.

To most this will just sound like a broken record repeat, as for the others hope this clears up confusion.