Changing emoji in /system?

[Gontier-Julien]

Hi,

So sorry to bother & this is really dumb, but i want to change the emoji in graphene os (my pc doesn't have enough ram to build it from source so i've found this).
I wanted to know if it was also possible because i can't get it working (can't mount the raw.img on my debian system).

It would be really awesome if it would be possible as i would like to avoid rooting graphene os just to change emojis.
So that why i'm trying to modify the NotoColorEmoji file in /system/fonts/

What i've done:

./avbroot ota extract -i ./tokay-ota_update-2025011500.zip -d extracted

cd extracted/

../avbroot avb unpack -i system.img

mkdir raw

mount raw.img ./raw

extracted/raw: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error.
dmesg(1) may have more information after failed mount system call.

Maybe it just something really dumb but i can't find what..

If it isn't possible i'll just take the L then.

Thank you in advance for any help !

[chenxiaolong]

That's not a dumb question at all!

In general, Android system images cannot be mounted like that until you resize it. These images are built with a special flag that causes duplicated data to be shared, so if one file was modified, it could potentially corrupt another file that shared the same data. To prevent that from happening, the kernel only allows mounting them read-only.

It's possible to work around this by resizing the image first with eg. resize2fs raw.img 2000M, which will "undeduplicate" any shared data.

However, I would recommend using https://github.com/chenxiaolong/afsr instead. I wrote this tool exactly for use cases like yours.

You can do something like this:

# Unpack the files from the image
afsr unpack -i raw.img

# Replace existing files
# NOTE: if you add a new file, you'll need to make sure there's an entry for it in fs_metadata.toml
cp your_replacement_font.ttf fs_tree/system/fonts/NotoColorEmoji.ttf

# Create a new image from the files
afsr pack -o raw.img

Modifying the image this way preserves the data deduplication and keeps the image as small as possible.

[Gontier-Julien]

Awesome i'll check this out this afternoon then!

[Gontier-Julien]

Update: it seems to have worked Thank you so much !

I can only test tomorrow or Tuesday tho when the phone arrive so i'll report back ^^