RogerBW's Blog

My Nexus 6P is jolly good, but its battery has become increasingly unreliable. So I now have a new shinyphone – also running LineageOS. This post covers all the gory details of getting it set up.

The LineageOS install instructions are here, but they don't go nearly far enough. Especially if you're not an Android expert.

In the stock MIUI interface, you need to turn on USB Debugging. Settings, About Phone has lots of hidden multi-tap options, including internal test routines. But the one you want is behind "MIUI version (For POCO)"; tap multiple times to get into Developer Mode.

Then it's Settings, Additional Settings, Developer Options, USB Debugging.

Here are the actual unlock instructions.

Create a Miui account at the official site, and get the MiFlash program. Install it on a Windows machine. (VirtualBox with a disposable evaluation Windows image works.) Install Mi PC Suite too. (Not clear whether this is actually needed. I went down a lot of blind alleys getting here.)

Under Settings, Additional Settings, Developer Options, Mi Unlock Status, Add account and device; log into your account on the phone. (You'll need a SIM in the phone for this.)

Under Settings, Mi Account, set the phone number for that SIM.

Shut down the phone, then power it up into fastboot (hold volume down and power keys).

Run MiFlash and make sure it's updated itself.

Run MiUsbDriver to install those.

Run MiFlash again.

Connect the phone.

Eventually MiFlash will admit the phone is connected and allow you to start the unlock procedure. I had a 72 hour timeout, during which you're supposed to "use the device". Well, the point of installing Lineage is not to have all my crap monitored... but I loaded up a few URLs each day, over wifi and via 3G.

I actually unlocked it after about 71½ hours, so maybe I could have got away with it earlier.

The phone is now unlocked, which has cleared everything but the basic operating system. So you need to get into Developer Mode again; see above.

Back out to the main screen, and on your PC run adb devices to make sure it's connected and authorised. (Authorise on the phone.) Now continue with the installation of TWRP in the official instructions.

There's another trick here. Once TWRP is installed, if you let the machine boot into the standard OS again, it'll wipe TWRP and reinstall its standard recovery. So from the fastboot screen, once you've installed TWRP, hold down volume-up and power until you get the "Pocophone" screen, which should then boot into TWRP.

Then you get told you need more recent firmware (and sites for this vary remarkably, as there doesn't seem to be an official source; searching for "pocophone beryllium firmware" seems to be the best bet), which you need to adb sideload before you can adb sideload the LineageOS image. (All the sites I looked at had the same files, which is either encouraging or very bad news.)

Then, finally within TWRP, Reboot → System. And get a warning: "No OS installed! Are you sure you wish to reboot?" The answer is, apparently, "yes". At least it's working for me…

I feel that this procedure is probably not something a typical user would be happy with doing.