Bitfields for Avance Logic board information:
Bit(s)	Description	)
 0-1	video RAM size
	00 256K
	01 512K
	10 1M
	11 2M
 2	???
 3	slot size???
	=0 8-bit slot
	=1 16-bit slot
 4	unused
 5	set on ALG2228/AL2301
 6-7	unused