3.9 Failure to identify SIM card
3.10 Failure to write IMEI
SIM is not identified
Touch Pin is
clean?
Clean SIM socket
Change a new
SIM to try
Is SIM socket
good?
SIM is damaged.
Replace it
Change a new one.
Check if VSIM1/
VSIM2 are OK?
Change U1420
N
Y
N
N
Y
Y
Y
Check each
signal on SIM is
OK?
Hot U1420 or change
a new one
N
N
Fail to flash IMEI
Could
it
power on?
To the part fails to power on
Could it
download?
Re-solder or
change PMU
U1420.
Re-plug USB cable,
re-flash IMEI
Re-solder or change
U1420
OK
N
Y
N
N
Y
Y
