Sim lock questions

[rs9000]

Hi,
I bought a htc one AT&T unlocked, now can I update my android version, rooted my phone and flash custom rom without losing the sim unlock?
And how can I re-unlock manually without a number code?
Thanks and sorry for my bad english

 

[xeni]

Hi,
I bought a htc one AT&T unlocked, now can I update my android version, rooted my phone and flash custom rom without losing the sim unlock?
And how can I re-unlock manually without a number code?
Thanks and sorry for my bad english

Once you sim-unlock your phone it will stay that way no matter what you flash. The only time the sim gets locked is if you get a new phone.

 

[rs9000]

Once you sim-unlock your phone it will stay that way no matter what you flash. The only time the sim gets locked is if you get a new phone.

I understand, so where is phisycally the block? How it work?