Micro SD as a cheap cartridge alternative

Just thinking about different formats for delivering games on the MEGA65. Of course, there will be Paul's awesome 4 MB floppy format and it would be totally disrespectful not to ship floppy games with it given the amount of effort he's spending on it. However, for those who don't like floppies because they're slow or it's easy to lose one in a multi floppy set (for big games), I'm also trying to figure out a suitable cartridge replacement as those are expensive to manufacture and have very limited space (can't hold said multi-floppy big games). So I thought about this:

Since the MEGA65 has the second Micro-SD slot which is automatically booted from if a Micro-SD is inserted in it, maybe Micro-SDs could be used as cheap big cartridge. One could realistically put custom versions of the OpenROMs sans BASIC interpreter that inject the game straight to the intended target address. Also a custom freezer that disable unwanted features like save states (no cheating). If I remember correctly, one of the nice things about this idea is that the OpenROMs allow raw reading of the Micro-SD card sector so one could also only do a minimal FAT32 partition that's only as big as required by CBDOS and Hyppo to boot the machine and load the main game PRG. The rest of the data could be put on a raw partition whose format is known only to the game.

What do you all think of these ideas?

Yes you could but cloning to a byte level from an external OS requires a bit more technical know-how than just copying files. It's kind of like needing Maverick C64 with the crack disk to remove copy protections back in the day. Plus, it's more of a challenge as a real concern since the retro-computing scene is small enough nowadays that pirating new retro releases will get you a 💩 blast on every forum. Gone are the Commodore clubs of my youth with the trade/want lists.

Problem is cartridges have limited space. 128kb ain't much. I was thinking of something like a MEGA65 game with streaming FMVs. Certainly doable with a class 10 micro SD. With the size of the screen and using the RRB and a full character set and four palettes, that would come at about 5 MB/s uncompressed. Huge AAA games on a retro-computer 🙂

Manufacturing costs mostly. I think you could find 4 megabits (512 KB) carts or even 8 megabits carts but that would be much more expensive and we're talking about products that have limited sales potential.

Can't add to my own post so I'll add by double posting. There is also the fact that C64 cartridges only expose 16KB at a time and you have to add extra circuitry to do bank switching in your cart if you want more. Take a typical SSI Gold Box AD&D game which filled four to six floppies on both side discounting the extra Adventurer's Journal which contained all the text they couldn't fit in the game. To make a cart that would fit this kind of game would be very complex considering the limitations of having only 16KB of the cart memory mapped at a single time. Maybe if you can fit the PRG and common data in 8KB and say that the other 8 is a scratch loading buffer or other schemes like that.

I had to go look on Knights of Bytes website to validate that Sam's Journey was actually available on cartridge and not just on floppy but indeed it is (but only in PAL format). Gist of it: clever coding for the cartridge version and, if you go look at Protovision's website, the cartridge version is more expensive due to the additional hardware for bank switching. Knights of Bytes would be best placed to answer how they achieved that feat.