This page covers all currently supported versions of the WR1300 - v1, v2, v3.
This TFTP method works to install OpenWrt on a device freshly opened
Setup a tftp server
Flash the device:
Update to latest OpenWrt:
If it's a soft brick (bad configuration, incorrect package selection, etc.) you can:
More info: generic.debrick
If you need to fix a firmware problem (for example, a bad build) and trying with reset or failsafe does nothing, it isn't possible to unbrick OpenWrt directly. The Cudy bootloader will start a TFTP client for OEM recovery using the Reset button, but this only accepts OEM firmware.
You need to reinstall OEM Firmware using the TFTP method and then reinstall vanilla OpenWrt afterwards.
The procedure is described by Cudy at https://www.cudy.com/en-us/blogs/faq/how-to-recovery-the-cudy-router-from-openwrt-firmware-to-cudy-official-firmware