In the MBsid_v2 user manual you can read about your sammichSID strange boot in ,
"the firmware saw "pressed MENU button :
"Updating Firmware to a new Version
Thats easy: just upload the new midibox_sid_v2 release to the master core with MIOS Studio.Once this firmware is booting, and the version number is displayed, press&hold the MENU button of your Control Surface to “clone” the new firmware to the slaves via CAN interface."
You can measure every resistor resistance for the 6 Pin Common Bus Resistor Networks. In the worst case not so hard to add an additional separate 10KOhm resistor, I think.