Wanted to share successful GOS installation story for a Used, Previously T-Mobile Carrier Locked, Google Pixel 9a I bought.
This is not my first Rodeo, I have installed and been running GOS on my 6a for 3 years now, and installed and ran a 6a for a family member, who has since upgraded to an 8 and continues on GOS. My 6a is breathing it's last breath and so i chose to save a buck and buy a used pixel for under $300. This is within my "security profile" im a more normal user who is just taking back control of my device from google.
I found a barely used 9a (25 battery cycles and reported 100% battery health) for a decent price in my area that the previous owner had bought locked from T-mobile and had paid off. They had paid for the device to be unlocked. I showed up and before purchase I asked to confirm if I could enable OEM unlocking. The phone had already been reset, so I went through initial startup by making a pin, without connecting to wifi or installing a sim. Once started, I enabled developer mode, and navigated to developer options, however OEM unlocking was Off, Greyed-Out, and had an X on it (not sure if this meant anything but thought it was worth mentioning). This had me worried, so I did some digging with the seller, who was very patient with me.
I first booted into fastboot, and the device stated in red that it was locked. My google searches inticated to me that carrier unlocking was a prerequisite to OEM Unlocking. I then read that likely (depending on the carrier) a factory reset and then starting up with a PIN (to enable OEM Unlocking) and connected to WIFI (to allow the bootloader to verify it's carrier restrictions?) might suddenly enable this greyed out feature. I read this might not be possible on Verizon. I looked up the phone by IEMI on google's pixel repair page and the phone was labeled as a "Pixel 9a Obsidian 128GB (T-Mobile)". While investigating this I had factory reset for a second time, but completed startup without a PIN but connected to WIFI (the seller's). So while we were on the phone with T-Mobile support, I factory reset the phone again (3rd time) and completed startup with a PIN and connected to WIFI. We asked the agent to unlock the phone and she said she did and asked us to check a couple of other things which were not in the settings such as carrier restrictions, which we could not find, possibly indicating that the phone had already been carrier unlocked as I suspected. She asked us to reboot so we did. The phone restarted, I then told her to wait, and I enabled developer mode, and went to developer options. To my delight, OEM unlocking was no longer greyed out. I enabled it, and input the pin. I then shut down, booted into fastboot by holding the Volume down button as I pressed the power button, and instead of being just in red "locked" the device was now "locked (unlockable)" in the same line.
That satisfied me, and I made the purchase. I shut down the phone and went home to see if everything was good.
I installed GOS without issue following the standard web procedure through Chrome on my computer.
Conclusion:
Used Previously Carrier Locked Pixels MIGHT be an option.
Contitions that might have allowed this to work for this device:
- T-Mobile had supposedly Carrier Unlocked the device after the previous owner had paid off the device completely. He showed me reciepts which I believed. This operation had been done some months prior (cannot confirm how many at the moment).
- Multiple Factory Resets
- Initial Startup from reset with PIN and connected to a WIFI network (probably a fast one, the seller was wealthy).
- Calling T-Moblie to confirm that the phone was carrier unlocked