[Acer Iconia Tab A100] pio_masaki:
Section 2: Recoveries and what they can do for you.

This section will cover recoveries and what they can do, and how to do it. I will be starting with TWRP, as I use that on all of my devices, and after that I will include a CWM section, as a lot, if not most, use that. They are similar in what they do, but different in where things are.

TWRP Recovery

Official TWRP for A100 by linuxsociety

This assumes you have already done everything in section 1, including installed ICS, rooted it, unlocked your bootloader, and installed TWRP custom recovery. Links for this information is provided in Section 1, in the post above.

First thing you should ALWAYS do when you enter recovery, before doing ANYTHING ELSE, is make a nandroid backup!

Getting into recovery: Depending on what ROM you use, this is done a couple ways. First is an AOSP ROM, like CM9/AOKP, which you can hold the power button, then select Reboot, then Recovery. In modified stock or rooted stock ROMs, this menu doesn't exist, you can either use an app like Quick Boot, and select recovery, or power off, then hold the Volume - key (closest to the rotation lock switch) and while holding it, hold power, once the acer screen comes up and starts saying Recovery kernel, release both and recovery will boot provided an update.zip is NOT on the root of your external SD card. This method works for any ROM.

Now I'm in recovery, what do I do? As I mentioned, make a nandroid backup before you do ANYTHING else! From the first screen (home screen) in TWRP select Mount. In mount you can leave everything alone and at the bottom will be two options with Circles. Select Using external SD Card for Backup. This will store your backup on your external SD card, never use internal SD if possible. After you select use external SD, press the Home button in the upper right corner. Now, back on the Home screen, select Backup. Double check the boxes checked are System, Data, Boot and Recovery. At the bottom is a nice little slide bar, slide that over and sit back. Takes about 4-5 minutes depending on how full your device storage is. This does NOT backup internal SD! After this is done, you have created a nandroid backup that when restored will put the system exactly how it was last time you used it. You can make multiple backups of multiple ROMs without issue, just however big your SD card is to hold them.

The restore menu, or the OOPS SAVE MEH menu is your best friend. This will restore you back to the last state your device was in for the backup that is restored. By default TWRP saves by date and time, however you can rename this with any file manager, never caused me any issues. Theonew reminded me of an MD5 issue that can happen on renaming backups, if this does happen, rename it back to the stock naming system to fix it. Generally I'll just append the ROM name to the front, so instead of 2012-6-14--18-25-01 it'll be CM9-2012-6-14--18-25-01. Make sense? That way to restore it in case of error, just drop the name. Easy. Theonew also did some testing, and confirmed that spaces in the folder name WILL cause MD5 errors and fail the restore, please use ONLY dashes and underscores (- and _ lol) in the folder name! To restore make sure you are on the Home screen, then select Restore. In the window you will see a list of your current backups, select one. Next screen has check boxes, make sure System, Data, Boot and Recovery are checked, then slide the bar to begin. This takes a bit, make sure you let it finish! Once done, your system will be at the last point it was used for that backup.

Advanced restore...I'm to lazy to reload and reset up my stuff after a ROM flash, so this is the fast and dirty way of doing it. If you flash a ROM and you don't feel like manually restoring your apps, you can uncheck System, Recovery and Boot, and leave only Data checked. This will restore your user installed apps and settings over the current ROM install. I don't recommend this for different ROMs, only for updates of the same ROM! Up to you but if you get alot of issues, you'll know why. After advanced restoring, go to the Home Screen and select Advanced, then Fix Permissions. Press Home again and select Wipe. Wipe Cache and Dalvik Cache, then reboot system.

Alright, enough already lets get our flash on! From the Home screen, select Wipe, then press on Cache, Dalvik Cache, Factory Reset, and System. Optional you can wipe Battery Stats if your battery seems off. Leave the rest alone. Once these are all wiped, go back to the Home screen, and press Install. The window on the left is your device folders, window on the right is contents of the current folder. I hope you remembered where your rom.zip is, because you select it here. Press on the zip for the ROM of your choice, then slide the bar to flash it. After that is done, select the left button Wipe Cache and Dalvik, then select Reboot system.

OK LETS ROCK THAT ROM! Woah, slow down scooter, there's a few things to do, or not do, first. After it boots, meaning it's past the boot animation and is sitting on the Welcome screen, set it down and leave it alone for 10 minutes or longer. Don't sign in, don't do anything, just leave it be for 10 minutes. If you can't think of what to do to manage the time you have to wait for awesomness of custom ROMs, read the thread of the ROM you chose. Set the thread for 50 posts and just read. After 10 minutes, hold the power key, and either choose Power off or Reboot, Reboot depending on ROM used. After it finishes rebooting (that was alot faster wasn't it?) you can go ahead and do the Welcome stuff, log in to Google, setup your device, download your apps, restore your apps etc. After restoring your apps (try not to restore app + data if possible, though I know games and stuff you'll want to) reboot one more time. After that second reboot, use the tablet as normal. From my experience this offers the BEST possible ROM usage, a vast reduction in lag, bugs, and oddness.

What else can I do with the TWRP Recovery? Well, the most useful tools are Backup, Restore (and advanced restore) and the wipe menu, plus fix permissions. Those generally can fix anything thats wrong. If you notice alot of lagging, FCs or general unruliness, wipe Cache, Dalvik Cache, and Fix Permissions. Another useful ability is ADB, which is beyond the scope of this section, but may be included generally in a later section. ADB can be used to repair otherwise bricked devices, and offers a very large amount of tools that you don't normally get to use in Recovery. Keep in mind ADB is powerful, and can quickly destroy your device, so please, be careful using it.

Placeholder for CWM Recovery section - coming soon!

CWM Recovery for A100 by ptesmoke