Selon d dieb13@klingt.org:
*) concerning the "too new firmware" problem: the only workaround i know to downgrade the firmwareversion (you can only do that in windows or macOS)
unfortunately the recent hdsp PCI cards (at least hardware revision v1.8) are not downgradable from fimware v11 to v10
it's sure that hardware revision v1.4 is downgrable (or has already the firmware v10) ; all the hdsp cards I saw running under Linux were v1.4