Thanks for the suggestion. Unfortunately I have some specific packages on my build, so I didn't use yours. Instead I also pulled some of the changes from the 3Gv2 patch into my build, more specifically, some parameters on the DTS file.
I didn't touch the "ralink,group" on the pinctrl section because it didn't seem relevant (and anyway I don't really know what that part is for and the meaning of the different parameters), but changed some addresses and the SPI frequency.
Let's see how this goes. Already flashed my device with this new build and looking good so far, but too soon to see if it's more stable.
Should anyone be curious, here's a patch (to apply from openwrt/master lastest commit) with the changes I made to try merging Roger's patch and the 3Gv2 currently proposed patch:
If it looks good, @rogerpueyo you can use this in your repo Also, can you make a pull request for integrating the support on the official openwrt tree?