Matronica wanted to load programs on his recently bought Amstrad CPC 464 (at the start of 2023). So he did create his ROM emulator using a Raspberry Pico which was announced in April 2023. In June 2023 he added on his card an USB port which let him use either the Albireo or Unidos ROM.

See the initial announcement on CPCWiki about his Amstrad CPC romboard using a Raspberry Pico, the sources are available on Github.