Matt Callow, a Amstrad CPC fan and a electronics guru has created a expansion module for the Amstrad CPC range of 8 bit computers. This module emulates the lower 8 ROM modules of the CPC. You can load ROM images from the PI Picos onboard 2MB of storage.
For more information about this interesting project, visit this page on hackster.io – Matt Callow Turns a Raspberry Pi Pico Into a Low-Cost ROM Emulator for the Amstrad CPC Family
Software and construction details can be found on the projects GitHub page CPC_PICOROM