Send Bass Station II patches (.syx files) to the FM-1, and back its patches up, over USB. This needs
Chrome or Edge, with the FM-1 running Bass Something 2 and connected by USB. The browser asks to allow SysEx: allow it.
The manual's SysEx section has the details.
Connect
Not connected.
From the FM-1: back up
Ask for the sound you're playing, or all 32 patches. Pressing SEL or FX on the FM-1's GLOBAL DUMP page (GLO three times) arrives here too.
Nothing received yet.
To the FM-1: load patches
A single patch loads into the sound you're playing: press SAVE on the FM-1 to keep it. A bank (each patch addressed to its number, as a backup from above or a Bass Station II sound pack) goes straight into the FM-1's patches, P01 to P32.
Drop .syx files here, or
No file chosen.
This replaces the FM-1's patches it reaches, without SAVE. Back them up above first if you want to keep them.