Reghack for the Linksys WRT1900ACS v2

Since the 5 GHz DFS channels are completely unusable with the WRT1900ACS v2 (see, I'm wondering does anybody know if there is a working reghack for that router?

I'd really love to use these channels but with DFS enabled they are just not working. I've applied the reghack found here: WRT1900ACS v2 how to update mwlwifi driver
but that only patches the world (00) and US region.
However, my router is hardcoded (eeprom I guess) to the FR region. So I'd either need a 'hack' which would allow me to switch my region or one which would patch the FR region.

From my reading I think setting the 'CONFIG_ATH_USER_REGD=y' flag would allow me to switch countries, but I have no idea how to do that as it would involve compiling the whole LEDE image (unfortunately that's far beyond my skillset).

I'm using the following LEDE built btw: