OPlus image utilities

Prerequisites

• JDK 8+
• Linux running kernel 5.4 or up (check with uname -r)
• I suggest not to use WSL as it has disabled SELinux and doesn't have erofs support by default.

OPlus rebuild script

• (NEW!) This runs all needed scripts for oplus image conversion and merging. Usage: sudo ./oplus-rebuild.sh

Image rebuilding

• Used to rebuild read-only erofs images into EXT4 mountable images. Usage: sudo ./erofs.sh <path to original image> <image partition name> For example, if I'm trying to make system_ext image ext4, I'll use the following command: sudo ./erofs.sh system_ext.img system_ext

• IF you're running into issues like "not enough space to setup filesystem", specify filesystem size by adding the size (I recommend 64MB) after $2.

Product image rebuilding

• OPlus (previously oppo) has been a jerk lately and keeps adding a butt ton of useless so-called "optimizations" (porting killers). This is one of them.
• In oplus Android 12 builds, OPlus has added OPLUS_FEATURE_OVERLAY_MOUNT to "mount product partition from existing my_* partitions" (to save image space? idk). With this going on, the product image shipped with OTAs is a dummy image that could not be mounted.
• Non-OPlus devices does NOT have OPLUS_FEATURE_OVERLAY_MOUNT implementation (and it is highly unrecommended to use it, as someone has bricked their devices before after implementing it). However, product image should NOT be empty (there is a system symlink pointing to /product). Therefore, this script is written to merge the my_* partitions into a single product image to replicate the /product behavior on OPlus devices.
• Note: The product partition might NOT be a dummy image, but might be a generic one, it has the device props! Not sure about the implementation at all but it seems like product image can be fixed to be mounted after all...

Usage: sudo ./product-merge.sh

OPlus custom partition merging

• We will still have to merge my_* partitions after building the product image (as not all files exist in product image). The script will automatically merge the my_* partitions into system.

Usage: sudo ./oplus-merge.sh

Notes

• All images (especially system) must be the dir that the script is ran.
• Make sure you have enough space. (probably like 27gb recommended)

To-Do

• Remove dependency of system file_contexts to build all images (we currently cat system filecontexts to the working file contexts to make the image resign properly)
• Run checks on mounting image(*) (It is reported by Velosh that sometimes mounting erofs images without -o loop -t erofs does not work. However it works on my PC, that's why I introduced this commit. Will work on checks for it later.)
• Make an argument for oplus-merge to either merge some odm files to system or create a separate odm image.

*: Regarding checks, when I mount an image with auto type but I never mounted with erofs type it won't be mounted, after trying -t erofs then mounting with t- auto the auto mounting works fine with erofs images, so I had to add a testmount method in erofs script, hit me up in the issues if your problem isn't resolved, in my case it did.

Credits and Thanks

Amack

Erfan Abdi

Velosh

Piraterex

PatrickFav

Rain2Wood

Xiaoxindada

And all those I forgot to mention.