found your post googling miflash guide
i dont know if i may post my device, redmi 9 activ, cattail, mediatek
the logs are attached
trying to downgrade to v12.0.10.0 downloaded here:
https://xiaomifirmwareupdater.com/archive/miui/cattail/
so that i can try a custom rom and this seems to be the only version that ill be able to flash them
through sp flash tool i can flash v12.0.18.0, after disabling cust
also can flash v12.5.6.0, but every boot start giving dm-verity device corrupted not trusted error and have to tap power button every time
those are the only two. trying to flash v12.0.10 through it gives STATUS_EXT_RAM_EXCEPTION error
so i flashed v12.5.6.0, entered fastboot and tried to flash through miflash following your guide, bootloader unlocked, got the exact same error described in your first post, so i figured it worked, only for it to be bricked again, after many attempts of flashing either a custom rom or v12.0.10