Tested by myself on a TA-1060. Should work with other models but I'm not guaranteeing it.
I claim no responsibility for anything that might happen to your device if you update. Updating with modified boot (Magisk/custom kernel) or custom recovery (TWRP) may render your device unusable until you flash stock firmware.
Some of these steps might not be needed, they are simply what worked for me. Feel free to optimize the list if you want.
First of all, check for updates. If it's available in your country congrats you don't need to do anything.
- Remove all SIM cards from your device. This is important because the device will get country information from SIM if one is present.
- Download a free VPN app (ExpressVPN and ProtonVPN are good ones I recommend). I personally used ProtonVPN.
- If your VPN app has a setting to block internet until the VPN connects, enable that. Also enable connecting on startup if you can. If not, remember to turn the VPN on as the first thing you do after booting later.
- Setup your VPN so it will connect to a country that the update has rolled out to. I used India, some other countries like Netherlands may also work.
- Disable WiFi.
- Go to Settings and delete App Data from the following apps:
- Google Play Services
- Google Services Framework (Enable "Show system" on the menu)
- Software Update
- Reboot your device.
- Connect to WiFi and make sure your VPN is connected as soon as possible.
- Check for updates.
If it all worked, you should be offered the Pie 9.0 update and can install it as normal.
Do not insert your SIM until the update has completed or it may cancel it. Once you've booted into Pie successfully, you can reinsert your SIM card.