New filament Sensor not detected correctly  

New filament Sensor not detected correctly

Hopefully someone may have seen this in the past. I have one of the original design MK3 that had the optical sensor, later it was updated to the MMU, and then later to the MK3S and MMUS spec which included the swap to the IR sensor (V0.1b). 

The original IR sensor was working but it was V0.1 which caused problems with newer firmware and is considered not supported. This caused all sorts of problems wit the filament not be loaded.

I purchased a V4.1 sensor from Prusa and installed it - but the firmware detected it as "V0.3 or below" (so its unsupported). After quiet a bit of time with a helpful support person we couldn't resolve the issue (checked cables, voltages, factory reset, downgraded firmware, upgraded firmware, etc).

In the off chance it was a bad sensor, they sent me a replacement, which I've installed but it is still seen as "v0.3 or older". even though it is reporting voltages of 4.4V and 0.3V which are the correct limits for sensor V4.1. If I put the old sensor in to test, it reports different voltages that are clearly for a V0.1. SO the mainboard is able to see a difference between the sensors.

In Summary - the voltages are being seen correctly, the mainboard is functional, the cabling is correct (have tried new cables) - but it is still detected incorrectly.

Any suggestions on what I am missing?