Here is Pirelli's version of the a_pwr_thresholds[] array (see pwr_cust.c in
the MV100 source), fished out of their firmware images:

Table begins at flash address 0x54C0C8 in fw version D910.0.3.98
Table begins at flash address 0x54B684 in fw version D910.0.3.99d

4170	100
4120	95
4070	90
4030	85
3964	80
3930	75
3900	70
3882	65
3847	60
3805	55
3786	50
3771	45
3759	40
3750	35
3745	30
3737	25
3719	20
3688	15
3663	10
3539	5
3370	0

Apparent voltage thresholds for UI battery icon change, determined by powering
a decased phone from a bench power supply, turning the voltage knob, rebooting
the phone each time and observing the battery icon:

from 3 to 4 bars:      between 3.88 and 3.89 V
from 2 to 3 bars:      between 3.77 and 3.78 V
from 1 to 2 bars:      between 3.72 and 3.73 V
from 0 to 1 bar:       between 3.52 and 3.53 V
"Battery Low" on boot: between 3.51 and 3.52 V

Below 3.37 V Pirelli's fw refuses to boot: starts, but then immediately powers
off.