A clever programmer (Daniel) created this special tool for Mega-Cart that does appropriate bank-switching and dumps the memory blocks to an IEC-based device — such as a Commodore 1581 floppy at .5mb chunks or the full 2mb dump of the cartridge to a more modern uIEC/SD device. There were some failure issues on every attempt, but interestingly enough, I could get a complete dump if I slaved the uIEC/SD off of the Commodore drive instead of directly hooking it up to the VIC 20 — guessing that it made for more tolerance during its write-phase. The programmer had no issues with his tool using a European PAL VIC, so perhaps the American NTSC version adds to the mystery.
Nevertheless, I am perfectly fine with a backup dump of my Mega-Cart, to be played using the new release of VICE 2.2 which supports the 2mb image, 8kb NvRAM, and all the appropriate bank-switching. Cool!!
xvic -cartmega mega-cart.rom -mcnvramwriteback -mcnvramfile mega-cart.nv