[Android Q&A, Help & Troubleshooting] danciuSU:
Lenovo Ideapad A10 solved soft brick

Hi,

I've recently bought this device and discovered this thread with enthusiasm.

I rooted the phone with Kingo and then I thought it would be a good idea to modify the screen density from 160 to 200, in build.prop. I was surprised to see it go into boot loop the next time I started it, but I thought I would go into fastboot and flash a backup or something.

Then I connected the device to my laptop and execute ./adb devices, with the result "?????????? no permissions" (I thought I was ****ed up at this point). I managed to get the device listed , but ./adb reboot bootloader (or reboot-bootloader for that matter) was just shutting off the device, hence I couldn't use fastboot to flash any recovery image.

./adb reboot recovery worked, I did wipe on data & cache, rebooted, but no success, still a bootloop.

I then did an ./adb pull /system/build.prop into my laptop and modified the density from 200 back to 160, and executed ./adb push build.prop back into /system/, but couldn't write into /system/, because it was read-only.

./adb shell with su, but it just hung up, with no result, so I had to exit.

I tried an exploit but it gave me an error, and then I pushed Motochopper, which rooted my phone, but then when I tried su in adb shell, it said Permission denied. My phone was rooted, but I still couldn't su into the adb shell. I thought that since Motochopper was able to install SuperSU onto /system/, it must have had root priviledges at some point, so I looked into the .sh file from the package, and deleted the last line, where it boots the device after gaining temporary root access (using the pwn), and then in adb shell there was a # instead of an $. It was the most beautiful thing on the screen for the day. I was root, only temporary but it still was something. I was able to remount the system partition as read-write, and adb push the changed build.prop file. Then I remounted the system partition back to read-only. Big mistake!

When I rebooted, bootloop. No root anymore, because of the reboot. But I thought I could run the same exploit again and do the same trick for the second time. Nope. The device could be rooted over and over, but after the process, the device would restart for no apparent reason, over and over again, no more root that I could use. Long story short, after some more attempts, I've downloaded an old update (2011) from another Lenovo Thinkpad tablet, and tried to sideload the zip, which gave me an error, but it seems that was the expected output for this trick. After that I did a cache wipe from the stock recovery, and when I rebooted the system was brand new, asking me for a Google account and Wireless connection and stuff. The SuperSU app was still there (obviously), but the phone wasn't rooted anymore.

I did root it again with Kingo, but for now I'm done with experiments on this device.

I'll wait for these attempts to become more popular, especially from people that know their stuff. And maybe find a way to fastboot? Now I'm thinking I could use the flash_all tool, since my operating system is running and I can write the file at any time. :laugh:

It seems you could also use kernelchopper to modify kernel memory and gain temporary root access, but someone has to look at the ROM:

http://xdaforums.com/showthread.php?t=2255491