Out of stock

[Discontinued] Gameboy 1MB 128KB SRAM Flash Cart with Custom Boot Logo

$33.40 USD

This re-programmable 1 MByte Flash Cartridge is like our regular 1 MByte but it features an ability to change the boot logo to one you design yourself. By using this feature, you will lose 16KB of ROM space so the maximum ROM allowed is 1008KB. Only works with the GBxCart RW flasher. Check out the How to use tab to see the steps involved.

This cart has been replaced by the 1MB 128KB Ultra Low Power Flash Cart which also supports the custom boot logo.

The custom boot logo works on: DMG, Pocket, GBC (05, 03), GBA 40pin
The original boot logo will appear on these devices: GBA 32pin, GBA SP, Super Gameboy

LSDJ users should select the MBC5 only firmware option and it will fail the ROM check because it’s missing the last 16KB bank (which is all blank) so you will need to restore an existing save file to it first. Works with GB Studio v1.1.0 with saving if you wish to develop your own game.

Questions? Jump on our Discord server where we and other users can help you or contact us via Twitter.

Check this list of Gameboy games to see the ROM/RAM size and MBC type your game will have. This cart works on every GB system – DMG, MGB, GBC, GBA, GBA SP.

Comes in a generic clear or grey Gameboy cartridge. Each unit is assembled in house and is tested on a Gameboy Advance. You can supply the ROM file for us to flash the cart if you like, it will be tested for 20-30 seconds to ensure it works.

We have different firmware available for different use cases:
MBC5/3/1 Hybrid (R1) – I want to play a good amount of old and most new games
MBC5/3/1 Hybrid + MBC1 1MB (R1.1) – I want to play more old games and most new games (slightly higher power consumption)
MBC5 only (R1.2) – I only want to play new games and use LSDJ

Once the firmware has been written, it can’t be changed unless you have the specific programming equipment (Altera USB Blaster). If you would like to change the firmware version, you can contact us and send the cart back to us for re-programming.

SKU: N/A Categories: ,


ROM: 1MB Flash (MX29F800C)
SRAM: 128KB battery backed with a CR2032 (should last 10 years or more)
MBC: MBC5 with MBC1 support (option) emulated with a Altera CPLD

MBC5/3/1 Hybrid (R1.0a):
MBC5 – Bank 0 gives bank 1 like in MBC1/3. Hybrid support for MBC1/3 games.
MBC1 support is limited to 512KB ROM / 8 KBytes RAM, it’s locked in “ROM Banking Mode” but without the 1MB ROM support.
Uses 54mA more compared to a regular cart.

MBC5/3/1 Hybrid + MBC1 1MB (R1.1a):
Same as R1 but add the 1MB ROM support to the MBC1 implementation (only tested with 1 game). The games that need this usually Japanese/Chinese games.
Uses 58mA more compared to a regular cart.

MBC5/3/1 Hybrid + MBC1 1MB (R1.1b):
Same as R1 but add the 1MB ROM support to the MBC1 implementation and 32KB SRAM (only tested with 1 game). The games that need this usually Japanese/Chinese games.
Uses 58mA more compared to a regular cart.

MBC5 only (R1.2a):
Implements MBC5 only.
Uses 48mA more compared to a regular cart.

The PCB finish is ENIG, Gold fingers (on the edge connector) with a 45 degree bevel to give the maximum life for insertion/removal of the cartridge.

This flash cart will take up additional current compared to a regular cartridge due to the CPLD so you will see a decrease in battery life; this is standard for CPLD based flash carts.

When you place an order, if you would like the flash cart to be programmed with a ROM, you need to supply it to us via email (you can reply to your order notification). It will be tested for 20-30 seconds on a Gameboy Advance to ensure it works, if it doesn’t work, we’ll contact you. If you don’t specify a ROM, it will be loaded with the LSDJ Demo.

Additional information

Weight 25 g

MBC5/3/1 Hybrid (R1.0a), MBC5/3/1 Hybrid + MBC1 1MB (R1.1a), MBC5/3/1 Hybrid + MBC1 1MB with 32KB RAM (R1.1b), MBC5 only (R1.2a) [recommended for most users]

Cart Colour

Grey, Clear

Cart Label

Yes, Not required, Include separately so I can place it later


Included, Not required

Pre-loaded ROM

I will provide a ROM to flash by email, Not required

Flash carts

Custom boot logo, Gameboy carts, GB Studio support, LSDJ compatible, MBC1 support, MBC5 support, Saving supported

How to use

1. Generate your custom logo using the Catskull GB Logo page, select Download ROM once you are done and accept the warning.

2. Download our Custom Logo Appender program.

3. Drag and drop the 2 ROM files – the one to have the logo changed along with the custom logo file you created. A new file called <originalfilename>_custom_logo.gb will be created.

4. Flash your 1MB flash cart with the <originalfilename>_custom_logo.gb file. Be sure to select the “insideGadgets 1 MByte 128KB SRAM Custom Logo Flash Cart” from the flasher menu.


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