EasyFlash 3 is the big brother of EasyFlash. It is compatible to EasyFlash, so usually all software for EasyFlash should also work on EasyFlash 3. But it can do more.
It provides 7 EasyFlash slots, each of them is a full-featured EasyFlash 1. With a menu you can choose which one you want to start.
Additionally it can replace the internal KERNAL with one of up to eight KERNALS saved in the cartridge. The external KERNAL has the same compatibility to software as if it had been built-in.
An USB port can be used to update the firmware on the CPLD. It will also allow to write to the cartridge from PC and to transfer other data.
The EasyFlash 3 also supports freezer cartridges. It is compatible with freezer cartridge images that can be run on any of the following freezer cartridges:
EasyFlash 3 is Open Source. The hardware design documents, HDL and software source code are available for everybody. EasyFlash 3 cartridges are available from different sources (but not from me). If you want to see the EasyFlash 3 in action, watch this (note that the video is outdated, the feature list from this page is more up-to-date):