Update:
Today, I tried to confirm that the workaround detachInterrupt(LOW_BAT_UC) returns the PMIC to previous Charging Performance since I have extensive test results for Boron Charging.
While the workaround does enable charging, It Does Not compare to previous results.
1.4.2 fails miserably when compared to the actual PMIC performance under earlier firmware.
Both Solar and Utility Powered when using the USB connector.
Since the Li-Po Charging issues are Chronic verses Acute, the typical user testing of the recent firmware before each user deploying to field devices didn’t catch it.
More testing should be performed for all Input conditions before the next significant change to System Power Manager 
. It has far reaching implications IMO.
The Device Update Thread doesn’t mention how to downgrade a Gen3 device from 1.4.2 (only Gen2).
Any suggestions to safely downgrade Borons?