Answer

You cannot flash BIOS back to older version with different AGESA code version because of AMD limitation.

Models

B350 KRAIT GAMING, B450 GAMING PLUS, B350I PRO AC, B450M BAZOOKA V2, B350M PRO-VD PLUS, B450M MORTAR TITANIUM, X470 GAMING PRO CARBON AC, A320M PRO-M2, B450-A PRO, A320M PRO-VD PLUS, X370 GAMING PRO CARBON AC, A320M PRO-VD/S, B450 GAMING PRO CARBON AC, X370 GAMING PLUS, B350M PRO-VDH, B350 GAMING PLUS, X470 GAMING PRO, A320M BAZOOKA, B450M BAZOOKA, B450M PRO-VDH V2, X370 KRAIT GAMING, B350M BAZOOKA, B350 TOMAHAWK ARCTIC, B350M PRO-VH PLUS, X470 GAMING PLUS, A320M GAMING PRO, X470 GAMING M7 AC, A320M PRO-VH PLUS, B350M GAMING PRO, B450M PRO-VDH, X370 XPOWER GAMING TITANIUM, A320M GRENADE, B350 TOMAHAWK PLUS, B350M MORTAR ARCTIC, A320M PRO-VD, B450M MORTAR, X370 SLI PLUS, X370 GAMING M7 ACK, B350 PC MATE, X370 GAMING PRO, B350M MORTAR, B350 TOMAHAWK, B450M GAMING PLUS, A320M PRO-VHL, B450M BAZOOKA PLUS, B350 GAMING PRO CARBON, B450 TOMAHAWK, X470 GAMING PRO CARBON, A320M PRO-VD/S V2, B450I GAMING PLUS AC, B450M PRO-M2, X370 GAMING PRO CARBON