Can't get second monitor working

[djeans]

 

By Build:

 

ASUS ROG Maximus XI Hero (Wifi)

Intel I9-9900k

PowerColor Red Devil Radeon RX Vega 64

32 GB Ram G.SKILL TridenZ RGB Series 32GB (4X8) (PC4 25600)

and i swapped the stock wifi card out for a Broadcom BCM94352Z DW1560 802.11a/b/g/n/ac WLAN + Bluetooth 4.0 M.2 NGFF Mini Card 867Mbps

 

Recently upgraded from Catalina to Big Sur - switched from Clover to Open Core on this one. So far, everything *seems* to be working except that I only have 1 monitor (connected via hdmi)

 

My other (main) monitor connected via display port does not work once booted (it does work to view the BIOS).

 

The boot args that I am using are : keepsyms=1 shikigva=40 shiki-id=Mac-7BA5B2D9E42DDD94

 

any suggestions would be greatly appreciated.

 

Thanks.