Matt Currie

The inside of a Game Boy Color with a switch wired to TEST1

A photo of a Game Boy Color showing the boot ROM being read, including the 2 bytes that are different to other revisions.

Managed to dump the CPU CGB E boot ROM by toggling TEST1 during boot. 48991ee7b1813d0cba5b099df6578668 is confirmed. Only 2 bytes different to the boot ROM seen on most other revisions.

08.04.2025 07:00 — 👍 7    🔁 1    💬 0    📌 0

Looks like LIJI32 over on Twitter was to spot the message I hid in the Game Boy's VRAM. Oh how I wish this was all real though! Happy April Fools! 😁

01.04.2025 19:34 — 👍 7    🔁 3    💬 2    📌 0

Looks like LIJI32 over on Twitter was to spot the message I hid in the Game Boy's VRAM. Oh how I wish this was all real though! Happy April Fools! 😁

01.04.2025 19:34 — 👍 7    🔁 3    💬 2    📌 0

Hmm interesting...

01.04.2025 11:29 — 👍 0    🔁 0    💬 0    📌 0

The boot ROM appears to have some similarities to cgb_boot.bin, so here is a BPS patch which can convert cgb_boot.bin to cgb_prototype_boot.bin here: mattcurrie.com/cgb_boot_bin...

01.04.2025 07:45 — 👍 3    🔁 0    💬 1    📌 0

I can't reveal how I obtained this (let's just say an uncle may have worked at Nintendo) but this Game Boy Color has a blue boot screen similar to other prototypes we've seen! I've been given permission to dump the boot ROM. See in the reply to this tweet to download it.

01.04.2025 07:44 — 👍 11    🔁 2    💬 4    📌 0

ded85933c7e1d0a7c4e3fb5e4251b67a

30.03.2025 10:04 — 👍 1    🔁 0    💬 0    📌 0