openwrt software was installed on my modem
I wanted to go back to the original software because there was no 5ghz support
I made a mistake somewhere and the modem is not responding. I cannot command the modem in any way
When I connect via serial port, I press any key but the boot does not stop.

last sentence on serial port screen
"Uncompressing ... LZMA: uncompress or overwrite error 1 - must RESET board to recovery
VR9 #"

it does not allow me to enter any commands after this section. When I throw a file with u-boot.asc it does not respond.
I  want to use my modem with its original software again.
I tried to recover with tftp server. but I was not successful.

I'm waiting for your help.