Edit phone number associated with device / SIM On my device, when I check the phone number through Settings > About Phone > Status > SIM Status, the phone number is incorrect. I ported my number over when I took out a new contract so I guess this is the number originally associated with the SIM. Is there any way to change this?

EDIT: Device is a Nexus 6P running M 6.0.1, no root.
A SIM contains multiple phonebook sections. One of them stores your SIM contacts. Another section contains "My Numbers" (MSISDN) with a max capacity of 3 numbers, usually. 

Unfortunately, my phones are too new to access "My Numbers", and my phones that are old enough (2005) to edit them are out of reach.

Fortunately, I had a spare SIM800 development board lying around. I hooked it up to my Arduino and started issuing AT commands.

Here's my conversation with my SIM card:

AT               &lt;-- Check if we are live and communicating with the SIM

OK

AT+CNUM?         &lt;-- Get own number

ERROR            &lt;-- CNUM failed, we don't have an "own" number

at+cpbs="ON"     &lt;-- Switch to "ON" phonebook: MSISDN (SIM own numbers)

OK

at+cpbs?         &lt;-- Get capacity of current phonebook

+CPBS: "ON",0,3  &lt;-- Notice that there's no stored number (0 out of 3)

OK

at+cpbw=,"+639950001234"    &lt;-- Saving my number

OK

at+cpbs?          &lt;-- Get capacity of current phonebook

+CPBS: "ON",1,3   &lt;-- Number saved (now consuming 1 out of 3 slots)

OK

at+cnum           &lt;-- Get own number

+CNUM: ,"+639950001234",145,,4    &lt;-- CNUM OK

OK

AT

OK


Unplugged, then returned SIM to phone. After that, my phone now shows my number +639950001234 instead of "Unknown".