Big news! I've successfully used an Arduino Uno to simulate the interface and was able to upload the IPL-demo program to an original console!
Video demonstration: https://youtu.be/jX9ZZXXkR2c

The IPL-MAIN repo has been updated with the Arduino sketch, wiring info, and usage instructions but here's ...

To add some further details:

FDS games in Nintendo's emulator offerings have always used their own format called QD (since FDS disks are based on Mitsumi Quick Disks). Some believe this format was initially used for the Intelligent Systems FDT ICE, given it can have up to 160K of extra SRAM ...

Not to sound brash but what good is there in saving the high score across play sessions in this game? It's not like VS. SMB or SMBDX where there's a high score entry/table or similar incentive to rack up high scores. NROM did have a battery-backed SRAM option used exclusively by Family BASIC (2K/4K ...

I've come up with an alternate license screen bypass which does not require enabling NMIs, including large final files, or lying about the file count. Instead, this method hijacks the IRQ handler by abusing mirrored addresses to overwrite the IRQ flag at $0101. Here's the required byte sequence ...

Yes, the leaked documentation from Color Dreams goes into a lot of detail regarding CIC stun circuit designs and their compatibility across protected and unprotected consoles. It seems like the end result was an 87% success rate on consoles they tested (13% failures).
Referencing MattKC's video ...

That's good to know, thanks.

Okay, I managed to dump the 18-in-1 cart after modifying the linked mapper 255 script to dump the correct PRG/CHR sizes. (PRG = 256KiB, CHR = 128KiB) It took several tries to match the hash with the known good dump, probably because of dirty/flaky pin connections. No dump will be provided here.

Yup, I came across 2 more bootleg carts in NZ. They were in a bundle with a legit Yie Ar Kung Fu cart. I'll post about them here in a similar format as before.

Hokuto no Ken: Pretty much this bootleg cart but with no labels on the PCB. The dumped ROM is identical to the legit cart, so it will not ...

A clean-room FDS boot ROM would certainly be a cool idea. I am about as contaminated as a non-Nintendo person can be re: the internal structure of the boot ROM, but if such an effort begins in earnest and someone with untainted eyes wants a thorough analysis, happy to be the dirty lab to your ...

It's funny to think that I'm probably responsible for there being more discussion of cart-to-disk conversions here than the other way around. :P

The main blockers when it comes to converting FDS games to cartridge format in the online age are (as you've already implied):

PRG-RAM writes outside ...

Hmm, Mesen2 doesn't exhibit this bug when forcing NTSC on this multicart. I checked both known revisions and even set the console type to the NES toploader.

https://www.nesdev.org/wiki/INES_Mapper_037 says:

This game, like Super Spike V'Ball + Nintendo World Cup, replaces PRG RAM with a single register to enforce multiple "jail cells" containing each game.

The Outer Bank Select register is cleared by the CIC reset line, so if this multicart is used ...

Toploaders (All Famicoms, NES-101) don't reset the PPU when the reset button is pressed. That 0.47 µF capacitor is solely for CPU reset, so there's no point in replacing it.

If you count regional variants which changed the mapper, there are plenty from Konami alone:

Contra (VRC2/UNROM)
Tiny Toon Adventures (VRC4/MMC3)
Akumajou Densetsu/Castlevania III (VRC6/MMC5)

Displaced Gamers covered those in a video theorising what the original mapper for Arc Hound/Contra ...

Okay, here's what I was able to reliably detect for the KS201 pins in question:

2 CPU A1
3 CPU A2
4 CPU A3
5 CPU A4
6 CPU A5
7 CPU A6
8 CPU A7
9 CPU A8
10 ?
11 CPU A10
12 CPU A11
13 CPU A12
24 ?
25 ?
26 ?


The ones with a ? mean that I couldn't find any connections with a smaller resistance than ...