HI, I am fairly new with OpenWrt but trying to get it on my Xiaomi router 4A Gigabit edition.
I have updated the stock firmware to version 3.0.10 and then followed the guide on https://github.com/acecilia/OpenWRTInvasion
After some time i connected my pc via USB to TTL on the board of the router to get some feedback out of the device.
I use the exploit as given pr the OpenWRTInvasion and i can start the flashing of the OpenWrt firmware.
I have tried the 21.0.1 both the sysupgrade and the xiaomi_mi-router-4a-gigabit-initramfs-kernel.bin (after each attempt I have "debricked" the router by putting the Xiaomi firmware back into the device.
This is part of the output I see on stdout after flashing the OpenWrt firmware (many errors related to SQUASHFS):
[ 386.200000] Link Status Changed: Port 4 linked Up.
router monitor is not running, exit.
[ 740.350000] SQUASHFS error: xz_dec_run error, data probably corrupt
[ 740.360000] SQUASHFS error: squashfs_read_data failed to read block 0x6d336
[ 740.370000] SQUASHFS error: Unable to read fragment cache entry [6d336]
[ 740.370000] SQUASHFS error: Unable to read page, block 6d336, size d5b4
Then it reboots and stops after starting kernel:
U-Boot 1.1.3 (Feb 28 2020 - 07:20:39)
Board: Ralink APSoC DRAM: 64 MB
Power on memory test. Memory size= 64 MB...OK!
relocate_code Pointer at: 83fb0000
RT2880_RSTSTAT_REG 0xc0030204
******************************
Software System Reset Occurred
******************************
flash manufacture id: ef, device id 40 18
find flash: W25Q128BV
env is right!
============================================
Ralink UBoot Version: 4.3.0.0
--------------------------------------------
ASIC 7628_MP (Port5<->None)
DRAM component: 512 Mbits DDR, width 16
DRAM bus: 16 bit
Total memory: 64 MBytes
Flash component: SPI Flash
Date:Feb 28 2020 Time:07:20:39
============================================
icache: sets:512, ways:4, linesz:32 ,total:65536
dcache: sets:256, ways:4, linesz:32 ,total:32768
##### The CPU freq = 575 MHZ ####
estimate memory size =64 Mbytes
RESET MT7628 PHY!!!!!!
Please choose the operation:
1: Load system code to SDRAM via TFTP.
2: Load system code then write to Flash via TFTP.
3: Boot system code via Flash (default).
4: Entr boot command line interface.
9: Load Boot Loader code then write to Flash via TFTP.
n3: System Boot system code via Flash.
Booting System 1
Erasing SPI Flash...
raspi_erase: offs:20000 len:10000
.
Writing to SPI Flash...
.
done
## Booting image at bc260000 ...
Image Name: MIPS OpenWrt Linux-5.4.154
Image Type: MIPS Linux Kernel Image (uncompressed)
Data Size: 4942436 Bytes = 4.7 MB
Load Address: 80001000
Entry Point: 80001000
Verifying Checksum ... OK
OK
Erasing SPI Flash...
raspi_erase: offs:20000 len:10000
.
Writing to SPI Flash...
.
done
commandline uart_en=0 factory_mode=0 mem=64m root=/dev/mtdblock8
No initrd
## Transferring control to Linux (at address 80001000) ...
## Giving linux memsize in MB, 64
Starting kernel ...
Nothing seems to happen after that 
Do you have some good advice to what I should try to do? is there are problem with the flash memory on my device? something else?
Thanks in advance
Michael
