Hello!
Since this board has power,reset and volume buttons, is there any keys combinations to soft/hard reset the board to default/vendor state.
I changed a setting in android and now the display is going crazy on me.
I know there is a board recovery doc, but the keys combinations is simpler if it exists.
Cheers!
Well, there is no existing combination to trigger factory reset (AFAIK), but you can simply erase wipe the userdata/cache partition in bootloader mode with fastboot.
Maybe something like adb shell recovery --wipe_data from a host would work also when device is booted and connected via micro USB.
Before you answered I went and did the steps to recover the board from [1] with images from [2]. I think this image is different from the one that came preloaded since now I the display works ok instead of just a vertical zone in the middle.
Anyway, I reproduced the initial problem and tried your solutions:
After you still need to write-back erased partitions (from [2] for example), otherwise the bootup will stuck, in my case at android logo.
The image from [2] does not have any recovery tool (or at least I couldn’t find it).
In the end steps from [1] are easy and fast enough.
Thanks and cheers!
[1] - Linux Host Downloads for MediaTek X20 - 96Boards
[2] - http://releases.linaro.org/96boards/helio-x20/mediatek/aosp/16.10/
He means erase/wipe as in one of the these;
rm /mountpoint/of/partition/* -rf
mkfs.ext4 /dev/partition
and not as in
dd if=/dev/zero of=/dev/partition
The difference is that with the former 2, you end up with an intact filesystem on the device, and with the latter, you have a completely blank (unformatted) partition.
When you write a userdata or cache image to an android device, it is literally an image of a formatted filesystem with nothing in it.
And you can make such an image like this;
dd if=/dev/zero of=partition.img bs=1 count={size in bytes}
mkfs.ext4 partition.img
When you run the factory reset option on an android device (system settings → system → advanced → reset options → factory reset), what it does, is it reboots into recovery with a command that causes it to format the userdata, and possibly cache filesystems.
When I’m working with a dev board, I’ll usually do a quick and dirty factory reset on an online system using the following;
[user@workstation ~]$ adb shell
$ su
# cd /data
# rm * -rf
# sync
# reboot
I did not use dd, I did
fastboot erase userdata
fastboot erase cache
Does erase command delete a partition (not just the contents) so it end’s up like there is no partition at all?
Your dd and dirty factory reset are very handy, thanks!
fastboot erase is akin to zeroing it out.
