Unable to make snapshots with "savevm" on OVMF guest

[xtec]

There are no issues with "offline" snapshots with qemu-img with the 
guest powered off.

However, with "online" snapshots through QEMU monitor I get this:

Error: Device 'pflash1' is writable but does not support snapshots

Indeed, it's trying to use the OVMF-vars "disk", which is of course not 
compatible.

I already did internet search, but at most they suggest "just convert 
the pflash1 to qcow2".
Hell! That's not what it is for.

Isn't there a way to tell savevm *which* storage to use?

Thanks.