Flash firmware using raspberry Pi

[oizo64]

Hello serrj-sv, I'm trying to downgrade firmware in my gateway [lumi.gateway.mgl03]. I have problem with transfering/sending data/command. I don't know why when i use cat /dev/ttyAMA0to see logs i see "uart ok" but when i use sudo ./mgl03_uart_recovery.expect | tee boot_gatewayv3_mgl03.txt i always see "art ok"

Power ON Gateway NOW!
art ok
strap pin:0x412b8ae2
enable spi-nand
ROM ver:v1.1, sig:455cc27, time:2016.01.04-18:42+0800, CPU(400 MHz), DDR2(533 MHz)
Enter ROM console
Connected to correct bootloader!
<RealTek>
alTek>
<RealTek>in:0x412b8ae c<
Unknown command !
<RealTek>gmsg 3

You can see it on attached log. boot_gateway_v3_mgl03.txt boot_gateway_v3.txt In logs i only delete empty lines. Next what i saw is that the xmodem not transfer data:

Xmodem sectors/kbytes sent:   0/ 0kRetry 0: Got 50 for sector ACK
Retry 0: NAK on sector
Retry 0: Got 45 for sector ACK
...
Retry 0: Got 61 for sector ACK
Retry 0: NAK on sector
Retry 0: Retry Count Exceeded
Transfer incomplete

Could you help me to resolve problem?

[oizo64]

Buying usb/ttl resolve problem.