Sounds like we are trying to do the same thing, as I am trying to install a CF Mech reader in my second A2000 with an Impact A2000-HC. I have another post here that I started about it. I burned the 3.15 rom onto a 27C128, and tried, to no avail. I think it may be due to needing the PAL upgrade mentioned above. If you have any luck, please share it with us, and I will do the same. Thanks.
