Thanks for the idea of bringing the batteries back outside the Reform.
My batteries were down to 0.3 ~ 0.6V and I used my lab power supply.
Interestingly when limiting the voltage to 3.2V and the current to 500mA the resulting voltage when connecting the batteries ramped up to 2V within a few (5-7) seconds.
I loaded them to get 2.8V which lasted about 40-60 seconds.
After ‘kicking’ all eight batteries this way they were at least at 2.6V when putting them back into the Reform which made the charging circuit accepting the batteries and properly charge them to the end.
Don’t know whether this approach fits the ‘specifications’ of the batteries - follow this idea at your own risk 
One day after this action the batteries are still at 100% - so I wanted to share my experience at least.