AM625: Android remount system as r/w

Munan Xu

Part Number: AM625

Hello,

I have a customer who's looking to make some local modifications to the filesystem.

mount -o rw,remount /dev/block/dm-0 /                              

'/dev/block/dm-0' is read-only                                                 

[ 2600.651149][ T1801] EXT4-fs (dm-0): re-mounted. Quota mode: none.

They are also unable to disable verity, even though the build is a userdebug build configuration:

builduser@grs-xerus:~$ adb disable-verity

/system/bin/disable-verity only works for userdebug builds

Overlayfs setup failed with error No such file or directory

Is there something else that needs to be set to enable modifications to the device filesystem?

Munan

over 1 year ago

0 Munan Xu over 1 year ago

TI__Expert 5060 points

Hello,

Any updates on this question?

Munan

0 Vishal Mahaveer over 1 year ago in reply to Munan Xu

TI__Mastermind 33390 points

Follow below commands over adb interface for remounting.

$ adb root
$ adb remount

-- Reboot the board --

$ adb root
$ adb remount

Now you should be able to push files to system/vendor partitions via adb push commands.

0 Munan Xu over 1 year ago in reply to Vishal Mahaveer

TI__Expert 5060 points

Hey Vishal,

Customer is seeing a partition size mismatch on adb which is causing the remount to fail:

PS C:\adb\platform-tools> ./adb devices
List of devices attached
0000000000000000        device
 
PS C:\adb\platform-tools> ./adb root
restarting adbd as root
PS C:\adb\platform-tools> ./adb remount
[liblp]Device size does not match (got 7516192768, expected 4831838208)
[liblp]Block device super size mismatch (expected4831838208, got 7516192768)
[libfs_mgr]add partition scratch
Overlayfs setup for /system failed, skipping: No such file or directory
[liblp]Device size does not match (got 7516192768, expected 4831838208)
[liblp]Block device super size mismatch (expected4831838208, got 7516192768)
[libfs_mgr]add partition scratch
Overlayfs setup for /vendor failed, skipping: No such file or directory
No partitions to remount
remount failed
PS C:\adb\platform-tools>

Any ideas on why adb is expecting such a different partition size? Or any ways we can ignore this?

Munan

0 Vishal Mahaveer over 1 year ago in reply to Munan Xu

TI__Mastermind 33390 points

Hi Munan,

I have only tried this on eMMC setup.
Is this SD card setup?

Regards,
Vishal

0 Munan Xu over 1 year ago in reply to Vishal Mahaveer

TI__Expert 5060 points

Hey Vishal,

Yes this board only has SD card as a boot option.

Munan

0 Munan Xu over 1 year ago in reply to Munan Xu

TI__Expert 5060 points

Hey Vishal,

Also, one other thing to be aware of, they do have dynamic sizing of the system and vendor partitions turned on, if we need to update the boardconfig.mk in any way to make the sizes match I think that should be doable.

Munan

0 Guillaume La Roque over 1 year ago in reply to Munan Xu

TI__Intellectual 2545 points

Hi,

vendor and system was in super partition so yes it's enabled but we don't do specific test to be sure it's working fine if on a update you change size of both partition.

guillaume

0 Munan Xu over 1 year ago in reply to Guillaume La Roque

TI__Expert 5060 points

Hey Guillaume,

Does this mean that they should just adjust the super partition size to match and this would work?

Munan

0 Munan Xu over 1 year ago in reply to Munan Xu

TI__Expert 5060 points

Hi,

Customer adjusted their superpartition size and was able to mount. Thanks for the help!

Munan

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AM625: Android remount system as r/w