Authenticating ADM on SIM card to change IMSI

Question

I have been reading the ETSI TS 102 221 V8.2.0 (2009-06) to learn how to interface with sim cards and using pyscard to interface with them in python.

I've been able to successfully read the ICCID and the current IMSI, but when I try to update IMSI I get '9804' back, meaning 'Access conditions not satisfied, authentication failed.'

PIN is disabled and update conditions for the IMSI file seems to be the admin number, which I have from the provider.
PIN is supposed to get authenticated via the "Verify Pin" command, but no such command seems to exist for the ADM number.

I've been looking at the "Authenticate" command, but I'm having trouble understanding it. I've found several APDUs online which people claim is the right way to authenticate ADM number, but none of them work.
Is there something more to authenticating ADM other than sending a normal APDU (CLA, INS, P1, P2, Lc(P3), <data>, Le)?

To summarize:
From the documentation, I can't find a way (don't understand enough, probably) to create an APDU which authenticates ADM number.
Any and all help or insight on the matter is greatly appreciated.

Answer 1

Try using 0020000A0X{ADM_KEY}, where X is length of ADM key in bytes.