Hi,
I am playing with a TP-link TL-WR741nd v4.3 router. Right now the only port working is the serial port and I have access to u-boot 1.1.4. As per instruction u-boot should have command "loadb" to load binary files through serial port using kermit. However, I can't find any loadb in this uboot. Am I missing something? Can't find loady for minicom either. How can I load the firmware through serial port?

hornet>  loadb 0x81000000

Unknown command 'loadb' - try 'help'
hornet> 

hornet> help

?       - alias for 'help'
bootelf - Boot from an ELF image in memory
bootm   - boot application image from memory
bootvx  - Boot vxWorks from an ELF image
cp      - memory copy
erase   - erase FLASH memory
help    - print online help
md      - memory display
mm      - memory modify (auto-incrementing)
mtest   - simple RAM test
mw      - memory write (fill)
nm      - memory modify (constant address)
ping.- send ICMP ECHO_REQUEST to network host
printenv- print environment variables
progmac - Set ethernet MAC addresses
reset   - Perform RESET of the CPU
setenv  - set environment variables
tftpboot- boot image via network using TFTP protocol
version - print monitor version
hornet> 

Regards,
M

(Last edited by mmrasheed on 28 Nov 2014, 19:46)

wow! pgid69 and his python script finalyl saved my day! Thanks!

For tp-link routers, where "hornet> " is the prompt, a little change in code's line would do-

change the line- 
if (buf.endswith(b"=> ")):
to-
 if (buf.endswith(b"> ")):  

Running the python script with --verbose showed exactly what was being copied to the memory.

 python ubootwrite.py --verbose --serial=/dev/cu.usbserial --write=openwrt-tl-wr741nd.bin --addr=0x81000000

It takes long time to copy the firmware in the RAM, partly because of the serial port speed. At some point, the script stopped with error. I tried again from the beginning and it ended up with an error at some other point. So, I modified the firmware to match the part the script copied successfully and then modified the address (--addr) and it resumed. After successful copy, I used the following code in serial console to copy the file from RAM to flash and then reboot. done!

erase 0x9f020000 +0x3c0000
cp.b 0x81000000 0x9f020000 0x3c0000
bootm 9f020000