i have the original msi b450 tomahawk, i tried m-flash but it says you cannot downgrade and flashback option doesnt work for me i tried many usb drives, can i flash via software?
must enabled downgrade option in bios ?
this is FIX for notebooks ,here must be some similar
or 2x same steps - try repeat
on mobo not exist this lock “warrnig is possible skip” in next round 
edit
or have flash button ? this is FORCE flash too 
I managed to downgrade it!!! This is my guide https://www.reddit.com/r/MSI_Gaming/comm…_usb_flashback/
Some similiar guide is probably also on win-raid
basic AFU way .,.but here not need this "advanced" flash
repeat select file -skips warning
or FLASH button - force flash