Netgear R6220 Not booting after openwrt upgrade

Hello,

I need your help.

I have a Netgear R6220 router for about 5 years, and in the last 2 I have used openwrt firmware.

Yesterday I tried to update the firmware at the last version and I think I made a mistake, now the router doesn't work anymore, so I soldered pin for the UART transmission, and this is the output (txt file, the text is to long per the message).

It seems is it in some kind of loop, but if I am fast, with CTRL+C I can enter in

U-Boot 1.1.3 (Sep 25 2015 - 10:29:47)
SERCOMM #

Can anyone help me to restore a functioning firmware (original or openwrt)?