Pirelli DP-L10 phone is a quirky Calypso target in that the same hardware
interface (USB) that provides access to the one easily accessible Calypso UART
also feeds charging power to the phone.  The result of this arrangement is that
whenever you connect your phone to your computer for communication, programming
or tinkering, the charging voltage is always present and the Calypso+Iota
chipset never enters switched-off state: every "soft poweroff" operation is
converted by the hardware into a deep reboot.

You can force a "cold programming boot" cycle on your Pirelli phone by removing
the battery, connecting USB to the "debattered" phone, running fc-loadtool on
the ttyUSB device that appears, and then inserting the battery in one swift
motion - this sequence will be necessary if you brick your flash and need to
unbrick it - but of course it is hugely inconvenient for ordinary FreeCalypso
tinkering (such as running FreeCalypso VPM firmware builds via fc-xram), and
doing it too often will ruin battery spring contacts.  The other alternative is
to let Pirelli's official fw boot fully (including GSM network registration) in
between cycles of fc-loadtool or fc-xram, and then do the switch-off operation
from the UI (press and hold red button on unlocked home screen) with fc-loadtool
or fc-xram running.  But this option is also unattractive, as it involves
unwanted SIM bring-up and GSM network registration from Pirelli's fw.

As of fc-host-tools-r19 we have an improved solution in the form of -Petmoff
option to fc-loadtool, fc-xram, fc-simint etc.  The usage scenario is as
follows:

* The phone needs to be in its "booted for charging only" state.  With Pirelli's
  official fw, this state is entered when you connect USB to a switched-off
  phone, or when you execute the switch-off sequence from the UI with USB
  connected.

* In this state, you issue a command like the following:

fc-loadtool -h pirelli -Petmoff /dev/ttyUSB0

or

fc-simint -h pirelli -Petmoff /dev/ttyUSB0

or

fc-xram -h pirelli -Petmoff /dev/ttyUSB0 ramimage.srec rvinterf

etc

This -Petmoff option (implemented as part of our generic boot control framework,
see Target-boot-control article) tells loadtools programs to send an ETM ABB
write (abbw) command to the target serial port, issuing a DEVOFF write to the
VRPCDEV register, just before going into the loop that sends beacons aiming to
interrupt the boot process at the Calypso boot ROM.  This trick works because
Pirelli's official fw implements a TI-standard RVTMUX interface on the Calypso
IrDA UART behind USB, complete with ETM, and with USB applying VCHG to Iota
VRPC, the DEVOFF operation (soft poweroff) turns into a deep reboot.

Running loadtools programs with -Petmoff against a Pirelli phone that is fully
booted, as opposed to "booted for charging only" state, is possible but not
recommended: it will forcibly kill the running firmware without any kind of
clean shutdown.  Strictly speaking, this option always effects the just-
described forced firmware kill, no matter which state the official fw happens
to be in, but if the fw is in its "booted for charging only" state, then there
are no ill effects to be concerned with.

When fc-loadtool or fc-simint/fc-simtool finishes with a clean exit, or when a
RAM-based firmware session started with fc-xram is cleanly finished with
fc-shell poweroff, the phone returns to the same "booted for charging only"
state.  Therefore, multiple operations of fc-loadtool, fc-simtool or fc-xram,
each with -Petmoff option, may be performed back to back, just like how a
FreeCalypso developer using a proper FC dev board would run back-to-back
sessions starting with -Pdtr or -Prts and ending with Iota poweroff.