November 21, 2019

17:11

I’m not sure if the HTTP User-Agent header matters for the login service (it does matter for market service), in case it makes a difference, here’s how to come up with one:

  APPNAME/VERSION (DEVICE ID)

Use either “GoogleLoginService” (earlier Android versions) or “GoogleAuth” (later Android versions) as APPNAME. I don’t know exactly when it got renamed, but it must have happened after SDK 16 and before SDK 19. VERSION may be “1.2” or “1.3” for “GoogleLoginService” and “1.4” for “GoogleAuth”.

DEVICE and ID are ro.product.device and ro.build.id from your 📁 /system/build.prop file.