The 6500s on our network run on WS-SUP720-BASE supervisor modules with the MSFC3 daughter card. Our baseline is to run 12.2(18)SXD7b. We ordered more sup720s which came in as WS-SUP270-3Bs. After I "downgraded" the IOS to our baseline, I cannot read from the sup-bootflash. The SP ROMMON is 8.4(2) on all supervisors. The RP ROMMON is 12.2(17r)S4 on all supervisors. Thanks for any ideas.