Hi, I'm unfortunately not familiar with the launchpad platform, but as far as I can see there were no further modifications after this change to EFA driver version 1.2: git.launchpad.net/libindi/commit/drivers...34a1d742e6dc3f57ac42 I have tried through different versions again in the last few days. With version 1.2 from the INDI package 1.9.2 I get the "Invalid checksum!" error as also described in this thread: indilib.org/forum/focusers-filter-wheels...handshake-fails.html I also tried the first suggested change of the checksum calculations ( link ) in version 1.2, but without success (the handshake still fails). Read More...