==== Commodore C64C JiffyDOS ====

You will need:

- A 27C256 EPROM
- Binary image of the C64C kernel (16KB)
- Binary image of the C64 BASIC ROM 901226-01 (8KB)
- Binary image of JiffyDOS (8KB)

Concatenate them together in this order: kernel + basic + jiffy images. E.g.:

''$ cat "kernel.bin" "basic.bin" "jiffy.bin" > system.bin''

Burn it to a blank EPROM.

Lift up pin #27 of the EPROM.

https://jammarcade.net/c64c-originaljiffydos-dual-booting/