To change an r9 390 bios to an r9 290 bios you would do the exact same thing.
Sapphire r9 290 tri x bios.
R9 290 4 gb.
Meet the sapphire radeon r9 290 tri x oc.
Added support for amd radeon r9 fury series r9 390 series r9 380 series r9 290 series r9 285 r9 260 series r7 360 and r7 260 desktop graphics products.
Today i got my hands on a new official vbios for my graphics card specifically the sapphire radeon r9 290x tri x oc 4gb gddr5 hynix uefi.
The bios can be toggled by the small black switch located on the top of the part closest to the mounting bracket.
An 8gb r9 390x bios file will flash to an 8gb r9 290x just fine but it causes issues with most 4gb cards and the same goes for the r9 390 to r9 290 br br b 3 b unfortunately i do not currently have the knowledge to hard mod any bios files using a hex editor.
The new version is 015 046 000 000 and it s far newer than the one my card came with from factory which was 015 042 000 000.
The amd radeon r9 290 and 290x comes flashed with two separate biosed for testing.
The first customized 290 series card in our hands sapphire s radeon r9 290 tri x oc is a rather straightforward semi custom card.