Unable to mount or format /Data <- Solution included

[ccdoggy]

Today I decided to flash AOKP for the a200, currently have it on my phone and so was aware of the process. I did not perform a nandroid (stupid move, i know). Upon performing the wipe of cache/data it got stuck at /data (I left it alone for 30 min and still no dice). I could flash roms but they would never boot up, just sit at the loading screen.

Looking deeper CWM could not mount or format /data. using ADB I could see that it was never getting mounted upon boot of the ROM and for some reason or other I could not format the partition. Tried CWM and Thor recoveries, both had issues with /data.

Spent a few hours trying different ROMs to no avail, then hit up ADB to see what the os was thinking about that partition. Looks like it was unable to touch it, could not mount, partition (format), get information, or really anything else. It was like it was corrupted beyond use.

Then I ran across the fastboot erase command. Not sure exactly what it does but it reaches out to a specific partition and formats it.

1. get into fast boot, turn it off and then hold power down and power then right when the screen pops up flick the rotation lock a few times, should say something about fast boot download mode. DO NOT USE VOLUME UP, it attempts to format a bunch of stuff and fails.
2. Ensure you have the drivers installed for the tab.
3. Download and extract the SimpleROOT application.
4. bring up cmd and cd to the SimpleROOT directory.
5. Run the command 'fastboot erase userdata'
6. DONT TOUCH IT. took mine about 5 min or so to complete.
7. Once done reboot into recovery 'adb reboot recovery' and perform the factory reset and install your rom.
8. Enjoy.

I believe this reaches out to the /data partition and performs a more reliable format and re-configuration of its settings to then be picked up and used by CWM/Thor and the ROM.

If that does not work for you I suggest starting your own thread, I just posted this here so that if anyone else encounters this then the search will pickup on this post and hopefully help them out.

[feelthefears]

This works AWSOME. THANK YOU SO MUCH. You have no idea how much trouble I've been through. I've registered just to say that.

For some that need more clarification and for people who have a500 with the same problem, download simple tool (works with a500, has simple root in it) or go to this thread to get the software.

If you can't get to fastboot mode get apx flash tool Dev-Host - APX_v0.4A-flashTool-500Manager1.0.2.zip - The Ultimate Free File Hosting / File Sharing Service, run it (install acer drivers first, links are in that software) and choose bundle 17 on the bundle market. You'll need your cpuid to flash, look for some threads how to get it in APX mode if you don't have it (apx mode is power + reset hole for 5 seconds). This bundle has fastboot option. So use standard volume up + powerbutton and rotation lock technique (after flashing) and you will get the menu where you can choose fastboot mode. Then proceed with the technique cdoggy wrote.

[teacherhh]

Hi,
I tried it, but I get an errormassage: Failed to process command erase: userdata error (0x19000000)

I can't get into fastboot mode without the POWER UP Button....might this be the problem?

[cykearney2107]

Hi,
I tried it, but I get an errormassage: Failed to process command erase: userdata error (0x19000000)

I can't get into fastboot mode without the POWER UP Button....might this be the problem?

hey im having the same exact problem, does anybody know how to mount data in fastboot?

[Rosco77]

I input the command to erase user data in fastboot about 20 minutes ago. In the command prompt is says that it completed after 75 seconds but on the tablet it still says "storMgr Formatting UDA". Should I move on to the next step or should I keep waiting?

update: I entered the reboot recovery command. It said "Daemon not running. Daemon started successfully" "error: device not found". The tablet still says "storMgr Formatting UDA". Its been thirty minutes now.

NEW UPDATE: It worked. The tablet never changed from the "Formatting UDA" message I mentioned above. I just held the power button to power off manually and rebooted into recovery manually. The only thing that is not stated clearly is how to boot into fastboot. You have to hold volume down + power, when the light appears on the power button YOU MUST RELEASE THE POWER BUTTON WHILE CONTINUING TO HOLD THE VOLUME DOWN BUTTON, when the tablet vibrates (before the acer boot screen appears) you must flip the screen lock switch while continuing to hold the volume down button.

[Rosco77]

For those of you having the "errormessage: failed to process command erase: userdata error". Try taking out your SD card. I was having the same problem the second time having to go through this process and I started freaking out because I didn't have that problem the first time. While I still had the error message showing while I was in fastboot I removed the SD card and tried it again and it worked like a charm.

[cykearney2107]

For those of you having the "errormessage: failed to process command erase: userdata error". Try taking out your SD card. I was having the same problem the second time having to go through this process and I started freaking out because I didn't have that problem the first time. While I still had the error message showing while I was in fastboot I removed the SD card and tried it again and it worked like a charm.

tried that and still getting the error message

[striker3034]

Never mind, I figured it out. I ran the SuperWipe again. Initial boot of SuperWipe said it couldn't locate /data, however it still formatted it during the wipe. Then I installed OTS update and it worked.

[Perf]

Never mind, I figured it out. I ran the SuperWipe again. Initial boot of SuperWipe said it couldn't locate /data, however it still formatted it during the wipe. Then I installed OTS update and it worked.

How long it takes to complete a superwipe on 16(32)Gb?

[Twister]

None of the existing solutions worked for me it always freezed the system. And after a freeze I could not do anything else with the integrated flash (eMMC).
So I sent the tablet back to Acer. The day I received it back I tried to flash a CM9 and it failed like the first one. Therefore I began to investigate, and finally found a solution, it needed a bit of hacking but here it is (For a 32Gb tablet) :
I made a 32gb image on my linux box, formatted it and uploaded it with fastboot.
The problem is : Fastboot won't allow the copy of a 32Gb image (way to big). Therefore I just uploaded the first 32Mb of the image and tries to repair the partition in recovery. e2fsck did a lot of fixes but finished by crashing because it was not able to write on some blocks. nonetheless It worked like a charm. CM9 booted. I'm now try to fill the sdcard with data to see if it works fine.

For those interested here is a small script for building the image on your linux box :

truncate image -s 29949427712
mke2fs -v -j -b 4096 -t ext4 image
tune2fs -O extents,uninit_bg,dir_index -C 1 image
e2fsck -fy image
dd if=image of=image_chunk bs=4096 count=8192

then :

fastboot flash userdata image_chunk

then in recovery (i'm using clockwork) :

adb shell
#e2fcsk -y /dev/block/mmcblk0p8

reboot and enjoy !