HP41 HP-IL : PROBLEM IN READING A PROGRAM (LIF) FROM A DRIVE

[aurelio]

Maybe a dummi question, forgive me in case. If I have to load a program via HP_IL (PIL_BOX) on a 41 from a media (virtual), which contains more than one PRG, how can I select, running READP the target? I'm not asked for which. I'm trying unsuccessfully to do it through PYILPER and maybe it does not work because the PRG is not specified and the operation stops on PACKING
Maybe it's about writing LIF on the DRIVE in particular way?

edit: typos