SIM PUK on EM7455

IoT Modules MC/EM Series
1

Hi, I accidentally locked up by AT&T SIM card by entering incorrect PIN too many times. Luckily I got the PUK code. For my AT&T card, it comes with PIN1 and PIN2, and PUK1 and PUK2.

Below is the sequence of command and response on how I got the card unlocked. But I have some questions about the responses from the card. I have listed by questions below. Can someone help?

Thanks

at+cpin?
+CPIN: SIM PUK
ok

at+cpin=,1111 /* is 1111 the new SIM PIN that I am setting for this card? */
ok

at+cpin?
+cpin: ready
ok

at+cpin=1111 /* why does it throw an error here? */
+CME ERROR: incorrect password

at+cpin? /* why does it ask for PIN2? */
+cpin: SIM PIN2
ok

at+cpin=2222
ok

at+cpin?
+cpin: ready

2

A related question is: “is there a way to raise the number of times I can enter a wrong SIM PIN before it locks up?”
Right now it is set to 3.

3

i guess this is set inside the SIM card.

4

Is there an AT command to change it?

5

Not quite sure but I guess we cannot as this is related to security.