Hi @alxgomz
I am in the same boat. As my rigs are pxebooting and headless, bios mods are painful.
Just whant to tell you my current solution. My rigs are identified by its macadress using ipxe scripts.
I changhe the default bootoption for that rig to WINPE and reboot it.
I build an winpe image which has vnc running by default aufter bootup.(google for that) From my lede router there is
a cifsmount as a working directory containing PBE/SRBPolaris/atiflash. This router is also the tftp and nfsroot host.
Its not what i want but the only solution i found(beside using nvidia GPUS)

AMD doesent care if you ask the support for help. atiflash hasnt worked for me on any of my boards including:
ASRock H110 Pro BTC+ ; Gigabyte H110-D3A BTC Edition ; MSI B250 Krait Gaming ; Gigabyte Z370P D3
I dont remember more i´ve tried. The "Freedos Solution" is failing also for me. (Adapter not found)
BR
derdigge