Before I installed the extensions it was not imnportant how empty the battery was. If I plugged the charger in when the phone was off, it charged without booting (showing the "big" battery charging icon..

Yesterday I let the phone discharge and then let the whole night charging. Even having less than 3% of the charge, when I connected the charger it tried to boot up. Meanwhile I pressed the power button for a couple seconds. It "switched off" and the charging battery icon was shown.

When I started it today (being still plugged to the charger) it "stucked" in the booting phase showing the nokia logo and playing the startup music. I never got the PIN request. It looked like a sort of booting loop. Sometimes the USB logo was shown in the upper right angle of the screen. Only once the carger was disconnected could I start the phone as usual without any problems.

I don't think this is an expected normal behavior. That's a very simple deduction:
- Without extensions: does not happen
- With extensions: it happens

Anyhow, it is not that bad. I will just have to make up my mind to this situation.