DataRover 840F ROM Flashing Card
JET very kindly unearthed a treasure chest containing the One True ROM Image for DataRover 840s, a PC Card that will flash a 840's ROM to Magic Cap 3.1.2j. This card can be used to re-flash a 'rover with no additional hardware. (See also this article for reflashing a 'rover using the developer tools and serial cable.) You can download the ROM image from the archives page and load it to a 8MB linear flash card yourself, or if you need a pre-flashed card mailed to you, contact me.
Note: if you bought a DataRover on eBay that has pre-release Rosemary firmware (usually dated 9/1/1997), that won't work with the packages in the archive. It's best to update to 3.1.2j.