[Tutorial] All-in-One Guide to the CMP741e: Rooting, Recovering, Backups, and ROMs

[spock1104]

This post is meant to be a one-stop guide to using pre-built modifications for the CMP741e tablet, partially due to popular demand and partially to recruit guinea pigs for the modding efforts in the ThinkTank thread. If you feel that anything is missing, let me know and I'll see about adding it.

DISCLAIMER: I do not take responsibility for any of these instructions breaking equipment or causing data loss.

Tablet Versions

There are actually two versions of the CMP741e tablet. Both have almost identical specs, 1GHz Allwinner A10 SOC (Coretex A8 CPU, MALI 400 GPU), 1GB RAM (shared with GPU), 4GB flash (split for all tablet storage, 1GB is system and 2GB is "internal SDCARD"), DMARD06 Gsensor, Realtek RTL8188CTV WIFI. The difference is the touch digitizer, some tablets are using the Goodix GT811, others are using the ZET6221.

Identify your tablet

The best known way to identify is to use a terminal emulator on the tablet or ADB from a PC to execute lsmod and see if the zet6221 or gt811 driver shows up in the list.

The manufactured date might also give this away. My GT811 tablets say July 2012. Please post if yours differs, or if you have a better identification method.

Recovering if something goes wrong:
Allwinner based tablets are near impossible to brick if you do something wrong. They're capable of reloading through USB with a program called LiveSuit or through the SD Card using a program called PhoenixCard. Both programs use the same img files. They're even capable of booting an OS from the SD card if necessary.

Use the instructions available on the Craig Website
If you have a ZET6221 tablet, use the recovery on the Craig Website
If you have a GT811 tablet, use my recovery image with phoenixcard.

Using ADB

1. Download and install the Android development tookit from here: Android SDK | Android Developers NOTE DOWN WHERE IT GETS INSTALLED
2. Install sdk tools, sdk platform-tools, and the google usb driver (in extras).
3. Plug in your tablet with debugging enabled (comes on by default, if you install a new ROM you'll need to enable it again). Do not enable USB storage.
4. Open a command prompt (cmd) on your computer. CD to the SDK directory, and then to platform-tools.
5. adb shell will open a remote shell on your tablet.

Rooting and installing Android Market
After ADB is working, you can root and install android market with the stock software. Follow the instructions at How to Root and Install Google Apps on the Craig CMP741D Android Tablet - TheUnlockr . Try running windowsstart.bat first. If that does not work, double click RootThat.jar. I've found sometimes the tool doesn't seem to do anything, just close it and try again.

Backing up settings and apps for carryover to new ROMs
Download Titanium Backup, install and run. Go to the schedules tab, and run Backup new user+system apps & newer versions. Then run redo backups for modified data.

Installing CWM recovery
Developers often package their software as zip files instead of img files. These zip files are installed using Clockwork Mod Recovery. The latest available for our devices is 6.0.1.2 at CWM Recovery 6.0.1.2 for Allwinner A10 LY-F1/TREQ Tablets - xda-developers. After rooting, unzip and copy these files to your internal sdcard.

Next, either from a terminal emulator on the tablet or from ADB:

1. cd /sdcard
2. sh install-recovery.sh

In order to enter CWM Recovery, enter sh reboot-recovery.sh

CWM Controls
Power is select, + is up, - is down, [] is back

Instructions after this point assume that you have installed an micro sd card. Doing so is HIGHLY recommended.

Backing Up and Restoring with CWM - Nandroid Backup
Before you do anything else in CWM, you should make a backup of your tablet's current state. This is usually referred to as nandroid backup.

1. Select backup and restore
2. optional: select backup method. by default, CWM does a diff every time you back up and only backs up differences. selecting tar will do a complete dump of the tablet instead (this works better for dev purposes)
3. Select backup

If you need to restore, later on, come back to this menu and select restore instead. You'll be presented with a list of dates and times you restored.

Installing new software
See post #2 for compatible ROMs and supporting files

When switching between different ROMs you need to follow these steps:
Note: Doing a factory reset isn't recommended, I've seen reports about it messing up the partition tables.

1. Mounts and Storage
2. Format /cache
3. Format /data
4. Format /system
5. go back
6. advanced
7. wipe dalvik cache
8. go back
9. install zip from sdcard
10. choose zip from sdcard
11. select the zip file for the ROM
12. if needed, choose zip from sdcard and select the compatibility zip
13. choose zip from sdcard, selet the gapps zip
14. go back
15. reboot system now

Upgrading software
If you're upgrading to a new version of the same release (say a newer version of CM10.1) then these instructions may be followed instead:

1. Wipe cache partition
2. Advanced
3. Wipe dalvik cache
4. go back
5. install zip from sdcard
6. choose zip from sdcard
7. select the zip for the ROM
8. if needed, choose zip from sdcard and select the compatibility zip
9. go back
10. reboot system now

Restoring apps and settings on the new ROM
At this point your tablet will seem brand new, but of course you want your old apps and data back. Download and install Titanium Backup again. Switch to the Backup/Restore tab, and one by one restore app+data for any apps and settings that you want to restore. DO NOT restore any system apps (usually shown in red in TB).

 

[spock1104]

This is a list of ROMs known to me to work with the CMP741e. If you know of others I should list here, please let me know.

BOTH TABLETS
Stock 3.0.8 Kernel
No compatibility zip needed, all features working
agk4444's CM9 ROM Android 4.0.4

No compatibility zip, but no camera or sound
agk4444's CM10 based on Christian Troy

GT811 VERSION ONLY
3.0.50 Kernel
Needs my 3.0.50 compatibility zip. Camera not working
pjotr25/myfluxi cm10 Android 4.1.2
ugers cm10.1 Android 4.2.2

3.0.62 Kernel
Needs my cmp741e_3_0_62_compatibility_alpha_1.zip - 573.41 KB. Camera not working
ugers cm10.1 Android 4.2.2 - Chrome tested and working on this version! - Some settings menus crash
CarbonRom 4.2.2 - Unverified but based on ugers' kernel

3.0.76 Kernel
Needs my cmp741e_3_0_76_compatibility_1.zip - 709.48 KB
Ugers CM10.1 - Tested, no menu crash!
79bass CarbonROM - Tested, hardware video possibly working?

ZET6211 VERSION ONLY
Stock 3.0.8 Kernel
No compatibility zip
jholt5638 d2pad CM9 port

GApps
http://goo.im/gapps
Make sure you download the version that matches the Android release you plan to use!


My recommendations right now are dependent on your expectations, and I can only recommend based on the GT811 since that's all I own. If you want to use the camera, agk4444's CM9 is the way to go. If you don't care about the camera, then think about stability. pjotr25/myfluxi ran near flawless for me, except chrome crashes. I'm running ugers 3.0.62 right now, which runs the smoothest of all of them and even runs chrome, but the settings crashes are a little annoying.

No matter the ROM, I recommend using Nova Launcher. The stock launcher and Trebuchet both seem to lag no matter what. If on Android 4.2, then Holo Launcher works well too (it only uses the 4.2 interface, so using it on 4.0/4.1 can be frustrating).

And lastly a call for help - I'm still trying to get the camera working with my compatibilities. See and participate in development progress in the ThinkTank thread!

 

[bama3416]

Nice job and very well put together how to and file links. I appreciate the sharing of hard work. Thanks

 

[wfg97079]

Great how-to. Thanks so much. Couple of questions. I got ugers cm10.1 Android 4.2.2 installed. Working well. - Couple of issues. First, I cant seem to uninstall apps. I think this is the menu crashing you referred to. Any other way to easily uninstall apps? Also, since the rom upgrade, I cant get adb console to work. Windows 7 only shows 3 drive letters. Seems to only be recognizing it as a drive. I have verified that I have enabled development settings enabled.

Nice job and very well put together how to and file links. I appreciate the sharing of hard work. Thanks

 

[spock1104]

Great how-to. Thanks so much. Couple of questions. I got ugers cm10.1 Android 4.2.2 installed. Working well. - Couple of issues. First, I cant seem to uninstall apps. I think this is the menu crashing you referred to. Any other way to easily uninstall apps? Also, since the rom upgrade, I cant get adb console to work. Windows 7 only shows 3 drive letters. Seems to only be recognizing it as a drive. I have verified that I have enabled development settings enabled.

Uninstalling still works through Google Play, ES File Explorer, or Titanium Backup. The biggest pain I'm finding with the crash is there seems to be no alternate way of switching apps to and from the "sdcard."

I suspect you didn't enable debugging (not just development settings), it's only turned on by default in the stock ROM. Go to the development options and enable root access for apps and adb, android debugging, and usb debugging notify. Then the telltale sign of if there's trouble is whether or not you get a popup on the tablet for usb debugging notification when you plug your tablet in. If the debugging popup doesn't show, it's more than likely a missing driver. Let me know and I'll hunt down the driver set if need be.

I also recommend turning on "Advanced reboot" for easy access to recovery when we get updates.

*Update* If you swipe right in Titanium Backup to the special features and scroll down, it can move apps back and forth.

 

[highroller]

Great work, someone should set it to sticky or official thread for cmp741e.

I have been using this for several months:
Stock 3.0.8 Kernel
No compatibility zip needed, all features working
agk4444's CM9 ROM Android 4.0.4

And it works great except that auto-rotation can't be disabled.


I am waiting for cm10 with all the features working, hope that it will be available soon. I want to try Google Now which requires Jelly Bean.

 

[spock1104]

ugers released a new CM10.1 and I updated the ROMs section. Be warned, he built it in such a way that if you update you'll also need to reflash gapps after the compatibility zip. Unfortunately settings still suffers from the telephony crash, preventing app properties from being opened.

camera might be possible with CM10 but not CM10.1 right now, there's some issue with the cedarx video decoder in ugers builds. Right now I think my specific camera troubles in CM10 amount to tweaks I had to make to the code to get it to compile. I copied sections of code from the gc0308 source code because the gc0329 source uses features that were in an A13 library but not an A10 despite an earlier section in the code that makes accommodations for the A10. I either need to come across some other source code or do some porting.

 

[wfg97079]

Fixed my earlier issues. What does ugers NEW CM10.1 offer over the previous one?
Any ideas on being able to move apps to the external sd card?

ugers released a new CM10.1 and I updated the ROMs section. Be warned, he built it in such a way that if you update you'll also need to reflash gapps after the compatibility zip. Unfortunately settings still suffers from the telephony crash, preventing app properties from being opened.

camera might be possible with CM10 but not CM10.1 right now, there's some issue with the cedarx video decoder in ugers builds. Right now I think my specific camera troubles in CM10 amount to tweaks I had to make to the code to get it to compile. I copied sections of code from the gc0308 source code because the gc0329 source uses features that were in an A13 library but not an A10 despite an earlier section in the code that makes accommodations for the A10. I either need to come across some other source code or do some porting.

 

[spock1104]

Fixed my earlier issues. What does ugers NEW CM10.1 offer over the previous one?
Any ideas on being able to move apps to the external sd card?

ugers' new build looks like a sync with the latest CM10.1 code. Biggest difference I've seen is that there is now an integrated superuser manager, accessed through the settings menu.

There are a few apps out there that script swapping sdcard and sdext or employ tricks to allow simultaneous use. I'm not sure which of these would and wouldn't work, and most seem to be developed for samsung devices only. If you don't mind the 2gb internal going "unused" you could also potentially edit /system/etc/vold.stab and swap them yourself permanently. I suppose there's the potential to repartition the internal memory to combine the internal data partition with the internal sdcard partition, gaining an internal 3gb plus your real sdcard.

 

[highroller]

What is progress on your fixes?

 

[highroller]

spock1104, have you fixed your problems? If so, would you upload them?

 

[highroller]

I installed ugers cm10.1 Android 4.2.2 with gapp and compatibility as described in post #2. It just keeps crashing randomly. I am going back to ICS.

 

[spock1104]

I installed ugers cm10.1 Android 4.2.2 with gapp and compatibility as described in post #2. It just keeps crashing randomly. I am going back to ICS.

I was seeing lockups on mine, ugers changed the performance defaults. try setting min cpu to 60 instead of 80 and the i/o scheduler to noop.

Unfortunately I may be out of commission for a while, my display died and Craig only has a 90 day warranty. I'm going to see if I can fix this myself, otherwise what I can do will be a little more limited. I have another tablet but that one is my wife's and I'll have to pry it from her when I want to do dev work.

That said, I have some hope for the camera working soon with 4.2.2. Allwinner apparently published a new SDK based on 4.2.1 that increases device compatibility and has better video drivers.

 

[Bubbabear64]

This is good information Spock1104. I followed your instructions and it was working within five minutes. Mine was manufactured in May 2012. It appears that it is a ZET6221 tablet. I did follow some instructions on using the system tweaks to change the processor speed to a minimum of 480 mhz to a maximum of 1.05 ghz using System Tuner Pro (It was amazing that the tablet was clocked at 60 mhz. I guess Craig gets a little nervous when there is a little heat in the unit. It didn't need to be that slow). That helped with the video streaming on Netflix (for most of the time) but I haven't been able to get Hulu + or Xfinity streaming services to work on it yet. The network is a wireless N using a Netgear router. Does anyone have any suggestions on getting the video streaming to work?

 

[zacanger]

Hey folks, quick question (yes, I'm new to this forum, but I'm a four-year Android user and CM user for 3 years). I got this tab yesterday, the ZET6221 version. Decent for the price, and I saw this thread so I figured, it's got a verified root method and some CM ports, I might as well check it out. It came rooted, with SU and Busybox, curiously enough.
I was running CM9 (not sure which one, they're all on my SD Card), and I tried using No-frills CPU Control, just to change it to around 600-1.3. Anyway, the tab acted up, screen started getting white lines and glitching out, so I held the power key 'til it shut off. Now I can't boot at all, just gets stuck on the Android logo. I've tried the Phoenix Card method twice, to no avail, and I can't seem to get it into FEL mode. Apparently you do that by holding any key besides the power key, press the power key for a couple seconds, release the power key, then press the power key a few times, but that didn't work. Still can't get past the little Android logo on boot. Any ideas? Or does anyone know of a way to get into CWM from power-off?

UPDATE: after a lot of work with a bunch of tools I don't really understand how to use, my tab is finally fixed and back to (basically) stock.