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How to enable ADB on ALLWINNER A13 9" - 4.2.2 - Windows 7 - error:device not found

27th January 2014, 09:33 PM   |  #11  
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I did briefly try the platform-tools (since I didn't mind the OS being trashed), they didn't add any adb_usb.ini and there isn't any real indication the file was needed/didn't exist, they could've simply put a note on the ADB utility when it didn't find any devices.

I'm not sure what ADB backup does. As far as I know the mounted partition images are differently named to various backup tutorials, so I get the feeling ADB backup just simply copies the user data and not much else. I recommend doing the backup I mentioned as well, it'll at least capture a copy of the boot partition, which if the device doesn't have that you'll probably need to revert to using live suite or some other firmware utility to restore it. Getting the firmware for that is another story, read a fair amount of posts here and other places on the net that don't sound fun.

I personally still can't get superuser to behave for using su on the terminal/term.apk (I want to remove useless "system" apps and make sure the device isn't talking back to anyone, i.e. google), but I'll keep tinkering.

My main aim for getting one of these tablets was to boot other firmware from the SD slot, but it looks as if the u-boot process is locked to internal NAND. So might have to modify it by adding "fatload mmc" to the script.



qUE
4th February 2014, 03:59 PM   |  #12  
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Quick Update;

Right the permissions thing turned out to be an issue with Superuser, dunno why. So replace the su binary from SuperSU (http://forum.xda-developers.com/show....php?t=1538053) into my SUME pack and install the Superuser.apk by;

adb root
adb shell mount -o rw,remount /system
adb push Superuser.apk /system/app



as for stripping back the Applications, I've got it down to this as bare bones

adb pull /system/app backup\system\app

to backup system applications before you do anything

I found if you do delete any applications and then android gets stuck at the logo, just adb push them back and it'll boot without reboot when you've got the chain right.

minimum applications needed for boot are;
DefaultContainerService.apk
DefaultContainerService.odex
SystemUI.apk
SystemUI.odex
Launcher2.apk
Launcher2.odex
Settings.apk
Settings.odex
SettingsProvider.apk
SettingsProvider.odex
ActSensorCalib.apk
InputDevices.apk
InputDevices.odex
FusedLocation.apk
FusedLocation.odex
LatinIME.apk
LatinIME.odex
PackageInstaller.apk
PackageInstaller.odex
ApplicationsProvider.apk
ApplicationsProvider.odex

A few odds and sods missing will make settings close, but it's trivial stuff. Personally don't like the sound of Fused Location, but it won't boot without it and I haven't seen any dodgey traffic from it (yet).

I recommend installing Droidwall with adb push /system/app, before installing games.
And modifying /etc/hosts with 127.0.0.1 to certain you know whos and advertisers.

Some of my personal choice replacement applications (so far);
Total Commander over ES file explorer.
Opera Classic over the inbuilt browser (although I'm still trying to remove the default search engine).



qUE
6th February 2014, 02:12 PM   |  #13  
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More update;

Discovered some new things;

BACKUP FILES WITH "ADB PULL" BEFORE MODIFYING ANY FILES!!!

I think performancepolicy.apk needs to be added to the bare bones application list, afaics from looking inside the package it sets system performance stuff, so likely throttling to preserve battery power.



bin_cfg.xml in /misc which can be modified by
adb shell mount -o rw,remount /misc
then adb pull, edit and push the file back

the line in there for "backlight_brightness" 780;1020;780 can be changed to 240;1020;240 which dims the backlight substantially saving battery power. not sure if 240 is the absolute minimum, but 120 seems to be too low afaics. interestingly information on the settings is in the files named _userview.xml



build.prop in /system which can be modified by
adb shell mount -o rw,remount /system
then adb pull, edit and push the file back
and then chmod 644 /system/build.prop

the lines in there for ro.wifi.signal.level.# can all be set to 0, this theoretically cuts the wifi power usage to less than 1mW, again saving battery. if android doesn't boot fully on reboot it's because chmod hasn't been set, you should be able to adb back in and correct.


please be careful modifying either file as both seem to have safety limits imposed on certain device components (i.e. battery temprature), messing with those can make the tablet stop working.



qUE
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