you have to read the manual. if you need the manual pm.
http://amiga.resource.cx/exp/comboi have scanned copy of manual and i also have hardcopies (cost of shipping + nominal fee). nice to have original manual if your card never came with it. i can also provide latest rom version and boot disk. it would be recommended to use rom 3.1 (seen also 1.3 systems with that card) - pm me.
as far as the screen with bad card check the orientation of rom. could also be bad prom chip. bah, lots of crap on ebay these days. few sellers bother checking what they sell don't they? thus, you'll appreciate the ones that do.
According to manual, Jumper 12 does the work for the board with 1 MB. J12 off means all RAM in banks 1 and 2 will be mapped as Extended Memory. J12 ON means RAM in bank 1/2 is assigned to Auto-config.
If you have 2058 then you will likely need to do J12 OFF unless you remove 2058. Amiga Architecture supports up to 8MB of Autoconfig memory. note 40 & 50 mhz boards have 4mb as factory installed (surface mounted).
This is all in user manual and you may want to buy one off me.
DO NOT MESS WITH THE JUMPERS UNLESS YOU KNOW WHAT YOU ARE DOING. YOU MAY DAMAGE THE BOARD.