the Xiaomi Mi Router 4A (100M International Edition V2) is not referenced in TOH; only the version 1 appears and the information on the Wiki is miss-leading.
This V2 covers exactly the reference in regards to the installation in point 3 from V1: Check the firmware layout with cat /proc/mtd and only proceed if mtd6: 00200000 00010000 “overlay”.
The V2 mtd6: 00100000 00010000
Please (to the moderators) update the TOH with the correct information and the link to: openwrt-24.10.2-ramips-mt76x8-xiaomi_mi-router-4a-100m-intl-v2-squashfs-sysupgrade.bin
because this is already available and works very well! Installation procedure is the same as the V1.
Check the firmware layout with cat /proc/mtd and only proceed if mtd6: 00200000 00010000 “overlay”
Download the openwrt-sysupgrade-image to /tmp and write it to the flash with mtd -r write <image> OS1
BUT, there is now a FW available for the V2 of this router, so the description should be equivalent yet for this version the 3.3 should have V2 mtd6: 00100000 00010000, like this: