I got a Samsung Galaxy S5 (SM-G900P, Sprint) running stock Android 6.0.1. As it comes, it's a CDMA phone, but I got it unlocked at a phone repair shop to use GSM and it has been working fine, but it only goes up to 3G.

If I flash a custom ROM (lineage-14.1-20171004-nightly-kltespr-signed), will my unlocked phone stop working with the SIM? or the unlock will remain after the installation?

P.d: I don't know if it's relevant, but I'm outside the US.

  • Don't rely on me as I'm not a developer, but as far as I know, flashing custom ROM has no effect on SIM, because unlocking SIM card has no link with phone. If you unlock it once, it stays unlocked in a different phone as well (you can actually check that). But as I said, don't completely rely on me. Commented Nov 3, 2017 at 3:48
  • Correct me if i'm wrong but the unlocking part happens on the phone not on the SIM. The process allows the phone to use the SIM but i don't know how to make that unlock persist after an instalation
    – RenierC
    Commented Nov 3, 2017 at 3:54
  • (@WrichikBasu i image the OP meant to ask if the phone will get locked to the carrier. )After a factory reset my phone didn't get locked back to at&t so i don't see why it should lock back for you. I might be wrong though
    – aBochur
    Commented Nov 3, 2017 at 4:02
  • As I said, I'm not confirmed in my comment, otherwise I would have given an answer. But the unlocking part is done on the SIM through the phone. The SIM is locked, not the phone. So I think it should remain unlocked. Commented Nov 3, 2017 at 4:02
  • SIM unlock is in the phone, once it is unlocked any SIM can be used without a check. The ROM itself is not relevant, you can flash any one you chose and it will not change the carrier SIM restrictions. Once it is unlocked, it's permanent. Note that this is completely different than a bootloader unlock, but that is not changed by flashing a custom ROM either, but depending on how the manufacturers stock ROM image is configured going back to stock could relock the bootloader but will still not relock the SIM.
    – acejavelin
    Commented Nov 3, 2017 at 20:55

1 Answer 1


I made it in 2 Samsung Galaxy S5 (Sprint) and it worked. They were unlocked and I flashed LineageOS.

But keep in mind, if you want to do this, flash the appropriate ROM. In this case, I flashed the LTE version instead of the Sprint version and it kept the unlock.

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