The Ultimate Guide to JiffyDOS: Speeding Up Your Commodore 64
In RetroArch with the VICE core, you can set "Core Options" to load an external kernel ROM. The term "hot" applies because changes apply instantly upon content launch — no core restart. jiffydosc64bin hot
Assumption made: you mean the command-line utility jiffyDOS (jiffydos) or a Commodore 64/1541 DOS replacement binary named jiffydos_c64.bin and you want how to load/use it ("hot" = hot-swapping or running from a modern setup). The Ultimate Guide to JiffyDOS: Speeding Up Your
Assign the drive ROMs under the Drive settings for Drive A/B. 3. Verification Put jiffydos_c64