Hi, I actually fixed my router C60 V1. As I already had UART access I used instructions from this topic:
https://forum.openwrt.org/t/tp-link-archer-c7-v5-eu-problems-to-unbrick/56374/5
Obtain an initramfs build for the model and version. These are found in the snapshot directory.
TFTP the initramfs build to somewhere in RAM (0x81000000 for this system)
bootm 0x81000000 to launch the initramfs build directly in RAM. The router is now running a full OpenWrt, but from RAM. This is only for recovery purposes since it can't save any files permanently, and won't boot again after the power is cut off.
scp a sysupgrade build to /tmp in OpenWrt.
use sysupgrade -n to flash this file. OpenWrt will take care of placing it at the right flash address and not damaging other data in flash.
But it would be nice if we had correct firmware for C60 V1 for tftp method as is the case for C60 V3 (link in first post).