This is the Marina 64, a new 1MB banked ROM cartridge for the Commodore 64 (and Commodore 128 and SX-64).
This is a common differentiator with TFW8b products. This will work for most people, most of the time. For the few who want to use different chips, or write in system etc. other products are available, but we try not to over complicate the main product for the average user. I was asked about the need to stack two 512K chips to get 1MB. I have seen a cartridge which requires this, but I don't see why that is necessary when you can use a single 27C080 1MB chip.
TFW8b.com. A production version will be available soon, with surface mount ICs pre-assembled, and an activity LED, which shows when the cartridge is active.
Magic Desk Cartridge Generator v3.0 by Žarko Živanov. This is a python script which can be used to compile a cartridge from normal PRG files. The script generates a menu program which allows you to select a program, which is then decompressed into RAM. The programs can span multiple banks, and with 1MB capacitor you can fit dozens of programs on a single cartridge.
C64 Cartridge Creator tool 1.0.0 by Solo761. There is no menu in this case, it just copies the prg file from the ROM cartridge into RAM and starts it running. None of these options are suitable for programs which require multiple files (for example disk games), only single prg files.