FGBWEB

fgbweb

Unofficial tool, version 1.4.
Reads and writes Game Boy cartridges over USB, in the browser.

Devicedisconnected

Tips

If no device is found, check in order:

The USB driver is installed. Running ModRetro’s official Chromatic Firmware Updater once installs it on first launch.
The Chromatic is attached with a USB-C data cable — a charge-only cable will not enumerate.
The Chromatic is powered on.
The official updater is closed, and no other tab has the device. Only one program can hold it at a time.

Then press Connect device again and pick GWU2X in the browser’s dialog.

If the console is not running the archival gateware, it is loaded into FPGA SRAM over JTAG and connection retried — nothing is written to flash, so powering off restores the console exactly as it was.

Disconnect matters. The archival channel is latched: it is released only by an explicit return to 115200 baud. Closing the tab instead leaves the console parked until you power-cycle it.

Cartridgenot read yet

Transferidle

Restoring or writing data overwrites cartridge contents. Always verify your backups before flashing.

Options

Append a timestamp to save filenames

Identify flash cartridges automatically

Writes command sequences to the cartridge. No erase or program is ever sent, and it is reset afterwards.

Validate the ROM against the database after reading a header

Reads the whole cartridge, so it costs a second or so per MiB.

Skip the confirmation before writing to a cartridge

Restoring overwrites the cartridge save. There is no undo.

Log

A text summary of the cartridge, the dump and the chip — what to attach when asking whether a dump is good.