Learning cycle starts below 3248mV (EDV1 stored in EEPROM), OS shutdowns device at about 3200mV (a bit less in fact), so to start a learning cycle you just need to follow simple steps:
1. Fully charge the device.
2. Let it discharge without pluging-in power to the [3200mV, 3248mV]
3. Plugin-in power before it shutdowns and fully charge.
4. Repeat untill there will be a right learning cycle.
I spent a lot of time to make it do a learning cycle, but finally it did.
Moreover about specific of learning cycle here