In the meantime I discovered a second synth that doesn’t respond well on the 2 subsequent RPN messages the E1 transmits after each sequence of 4 NRPN messages, i.e. the preenFM2. I already built my own simplified NRPN function to deal with that. Simple enough but the downside is that any control that should have been a NRPN now has to be set as a Virtual controller. The issue is that the preenFM2 doesn’t use SysEx parsing but relies entirely on a one time transmission of all NRPN’s into the E1 for setting the parameters right. And there is going to be more work involved to reconvert all those received NRPN into virtuals. A setting in the E1 for simplifying NRPN use (without the RPN ) would be welcome.