Reported by Nikolaus Schaller, Jul 10, 2014

Please consider to have a 10uF capacitor on modem VDDLP (M15), 
see "PHS8-E_Hardware_Interface_Description":

[quote]
3.3.6  Automatic Reset
An automatic reset takes effect if
* A sudden momentary power loss (SMPL) occurs - e.g., a very brief 
battery disconnect - and
the power returns within 2 seconds.
The SMPL feature ensures that if VBATT+ drops out-of-range (< 
2.55V nominal) and then re-
turns into range within 2 seconds, the power-on sequence is executed 
and the module switches
on again. Thus the SMPL feature achieves immediate and automatic 
recovery from momentary
power loss such as a brief battery disconnect.
To employ the SMPL feature the VDDLP line has to supplied for at 
least 2 seconds after a pos-
sible power loss (e.g., by connecting a 10μF capacitor).
[/quote]

It's not entirely clear to me if settings like PIN / AT+CFUN etc are 

persistent over a reset/power-on sequence, but anyway seems 
this is a feature we want to at least test and possibly exploit.