The project is to maintain a treble-compatible vendor image for SHARP AQUOS S2. Make it fit to the latest Android version as possible. As of writing, the image had been tested under phhusson's AOSP 9.0 GSI. Check the Wiki for more compatibility details.
It's aimed at SHARP S2 phone, however the repacking kit may also apply to other phones provided with proper fs_config, file_contexts and vendor files.
Project Treble introduces the architecture that decouples the 3rd-party vendor services from the Android core system. That is, a treble-compatible phone could be upgraded to the newer Android version without involving its device manufacturer too much.
To put it in simple words, you can have your /system and /vendor be independent. A fastboot flash to /system_a shouldn't cause the need to flash /vendor_a as well.
SHARP AQUOS S2 is a treble-compatible phone, and with its latest version of Android 8.0 (firmware 2.080WW), it can have its /system to be flashed to AOSP 9.0 GSI and is workable. However FIH seems stopping maintain the phone and there still some components not being well decoupled from its stock /system partition. So the project here is try to make those components work in newer Android version by decoupling them more deeply.
It's developed on Ubuntu 18.04 and will required the following packages to be installed.
sudo apt install libpcap2-bin make git
And if you need make test to test repacking, should also have the following ones.
sudo apt install android-tools-fsutils sudo
It also comes with a Dockerfile for testing.
Clone the codes, and in the project folder, type make
~/w/sharp_s2_treble_vendor_image ❯❯❯ make
bin/generate_fs_config.sh vendor > fs_config
cat etc/plat_file_contexts vendor/etc/selinux/nonplat_file_contexts > file_contexts
contrib/make_ext4fs -s -l 1073741824 -L vendor -a /vendor -C fs_config -S file_contexts vendor_95ac217.sparseimg vendor
loaded 3125 fs_config entries
Creating filesystem with parameters:
Size: 1073741824
Block size: 4096
Blocks per group: 32768
Inodes per group: 8192
Inode size: 256
Journal blocks: 4096
Label: vendor
Blocks: 262144
Block groups: 8
Reserved block group size: 63
Created filesystem with 3135/65536 inodes and 155805/262144 blocks
to generate an repacked image from the current git tree.
Test is achieved by comparing the required file system attributes between the created image and the stock one. In the project folder, type make test and it will ask for root permission for mounting & umounting target images.
This section describes how the built image can be used or be cooperated with other GSI ROMs.
In a stock SHARP S2, there are about 82 partitions on the disk but not just /system and /vendor mentioned before. All the partitions somehow interact with each others under the table and thus increase the complexity if some had been modified previously. (might be due to a customized ROM).
The guide below is only (tested on) for a stock SHARP AQUOS S2 4GB/32GB, version 2.080WW. I didn't test on other model/firmware.
- You should have your bootloader unlock.
sudo apt install android-tools-fastbootsudo apt install android-tools-adb(if backup needed)- any treble GSI image, for example the AOSP 9.0 from phhusson.
- and the image you built
vendor_xxxxxxx.sparseimg
Note that on Ubuntu 18.04, install android-tools-adb will have udevd rule set up for you. The phone should be detected correctly when you plugged in.
S2 is an A/B phone, which means it owns 2 slots for each system partition. We can install our images to the inactive slot and thus leave the current stock 8.0 slot untouched. Shutdown S2, and have it plugged in your PC, press Volume Down + Power to boot into Download mode.
> fastboot getvar current-slot
current-slot: a
Or it could a b in your case. It depends on how you upgraded your phone.
Assume you are on a stock 8.0 S2 (2.080WW), then by default, the other slot, which is inactive now, would be your previously environment, e.g. the stock 7.1.1 (1.35F WW) . This is how A/B phone works for OTA update. So for this example it would look like this:
| PART | Slot A (In Use) | Slot B |
|---|---|---|
| boot | kernel installed by 2.080 | kernel installed by 1.35F |
| system | 8.0 | 7.1.1 |
| vendor | 8.0 | 7.1.1 |
> fastboot --set-active=b # next boot will from slot b
After setting slot b, Android will use boot_b, system_b, vendor_b, and xxxx_b partitions to boot. So now we just need to flash both the system_b and vendor_b to our provided images.
# use the 9.0 GSI *su* version for easily backup slot a
> fastboot flash system_b system-arm64-ab-gapps-su.img
# and then the built vendor.img
> fastboot flash vendor_b vendor_xxxxxxx.sparseimg
Now it looks like this:
| PART | Slot A | Slot B (In Use) |
|---|---|---|
| boot | kernel installed by 2.080 | kernel installed by 1.35F |
| system | 8.0 | 9.0 |
| vendor | 8.0 | 8.0 (this project) |
And good news is that the kernel installed by 1.35F is able to boot into GSI 9.0 as of writing.
Before going to new system, we have to erase user data first because the partition is shared to both slot_a and slot_b, compatibility issues will happen and thus failed to boot.
# !!!!will lose all your data!!!!
fastboot format userdata
# reboot~
fastboot reboot
After going to a new system, I suggest use adb to su to backup stock boot_a, system_a, vendor_a just in case. Also suggest update kernel in boot_b to be the same as boot_a.
> fastboot flash boot_b boot_a.img.that.you.just.backup
- A3sf6f - Initial work
- heineken78 @ XDA
- rkhat2 for
make_ext4fs