You need to obtain the `vbmeta` and `vbmeta_system` images for the corresponding model (from the Chinese firmware). Disable AVB verification on them using an appropriate method, then flash them in EDL mode. Next, you will need older versions of the `recovery` and `abl` partition images (dating before version 3.5.2) so that you can flash the `system`, `system_ext`, and `vendor` partitions in Fastboot mode. Alternatively, if you cannot obtain older `abl` or `recovery` images, your only option is to flash the entire Global `super` image via EDL mode.
You must manually edit the partition image information; using the --disable-verity --disable-verification flags in Fastboot mode is ineffective. Furthermore, if you cannot truly disable the AVB verification for the vbmeta and vbmeta_system partitions, flashing any unofficial vendor image will result in a boot failure.
Actually, the method above is unnecessary. Here is what you really need to do:
1. Disable AVB verification on the `vbmeta` and `vbmeta_system` partitions.
2. Extract the current version of the `super` partition in EDL mode and locate `vendor_a.img` (or `vendor_b.img`) within it.
3. Find a tool capable of editing partition images, such as
TIKhttps://github.com/ColdWindScholar/TIK.
4. Modify `/odm/etc/build.prop` inside the vendor image: change the value of `ro.product.odm.model` to the corresponding Global/International model identifier.
5. Use the partition editing tool to repack the modified vendor image and the remaining parts into a new `super.img`, then flash it in EDL mode.