Sounds like the firmware is borked… I’m less familiar with Simplex errors, but the late great @Retired_STR-SG (A former Simplex Technician) posted some info on a 4008 that may be helpful to you: Simplex 4008 possible problem - #6 by Retired_STR-SG
Sounds like the firmware is borked… I’m less familiar with Simplex errors, but the late great @Retired_STR-SG (A former Simplex Technician) posted some info on a 4008 that may be helpful to you: Simplex 4008 possible problem - #6 by Retired_STR-SG