That's news to me then. There's no reason a chip should get 'locked' on that board.
Looks like it could be done on the H81M-Plus, with BIOS 2110
https://www.youtube.com/watch?v=4w41XjH_Y7c
You have a slightly different board, and slightly different BIOS numbers.... so I'm not sure.
What BIOS revision are you on currently?
Version 2001 brought support for the G3258, so if you're having issues and can flash the BIOS to older versions, that would give you the best chance of 'full scale' support - but I doubt it's necessary.