Hi,
I’ve been having too many stability issues after upgrading my AM4 motherboards to latest beta versions. Both of the boards has ryzen 1600 installed, the built in BIOS flash tool won’t let me downgrade. My motherboards are:
MSI B350M PRO VD PLUS
ASROCK X370 PROFESSIONAL GAMING
I successfully downgraded MSI B350M PRO VD PLUS using “this guide” but while flashing asrock it gave me an error 43 and now it stuck on boot loop and gives code 79 on debug led.
Its not for the lack of warnings that all OEM put in their bios update descriptions…for sure, regarding AM4 update bioses, all the rest is user fault.
Their warning is real…a lot changes in updates to the SPI/EC that will never be compatible with downgrades, so thats why the warning exists. Get a CH341A SPI flasher and good luck.
0x79:
CSM initialization
0x4X:
0x10 – 0x2F
PEI execution up to and including memory detection
0x30 – 0x4F
PEI execution after memory detection
0x50 – 0x5F
PEI errors
EDIT: In forum will find plenty of info about the CH341A SPI flasher, success and fail cases, specific for some motherboards, etc… your time to search.
Thanks for the reply, and I would like to ask that why did you wish me good luck? I mean is there a chance that CH341A SPI won’t work? Are there any alternatives to CH341A SPI? such as CH341A 24 25 Series? as CH341A SPI not particularly available in my country.
well he meant good luck on flashing it 
CH341A/CH341B that got 25 and 24 SPI would work. best you buy that programmer along with soic8 clip and 1.8v adaptor (since some recent bios chip use 1.8v).
I already ordered, hopefully it will arrive on tuesday.