[Windows Phone 8 General] charlotteplusplus:
I always wanted WP8 GDR2 on my 1020, because I have this version on my 640 and 1520, and it gives the best Windows Phone experience. Everything is smooth, the settings menu is tidy. I just like it a lot! It used to be easy to do with the Insider program. However, most of the methods that worked before no longer work. So I wrote this guide that works NOW. I have tested it, except the W10M part as I don't have a spare 1020 to do that :(

This guide is for the 1020. For other x2x, there is a WP8 tutorial on http://forums.windowscentral.com/up...hone-8-1-gdr2-without-sd-card-x2x-series.html and if you prefer W10M, some custom ROM with GDR2 that will let you update to W10M on https://xdaforums.com/windows-phone-8/development/lumia-520-625-820-windows-10-upgradable-t3421005

Follow the steps "a" for WP8, and the steps "b" for W10M

1ab. On your windows7 computer, setup WPInternals, and flash the FFU matching your model. You need to download various files. There is a great tutorial with step-by-step details on https://xdaforums.com/lumia-1020/help/lumia-1020-updating-to-windows-10-t3531645

Read the guide, but stop after flashing the FFU.

2a. If you want to have W10M, jump to step 2b. If you want to have WP8, let the phone update normally instead.

Quick explanation: after installing the FFU, you will be on version 1424.0000. You can unlock the bootloader if you want, but because you need to let the phone update, do NOT root the device. Rooting will make the update fail with error 8007000d.

So just go to settings, check if updates are available, install, let it run it course. You will now be on version 14234.375, which is the last one the Lumia 1020 could get officially

3a. Now you must unlock the bootloader, then root the device. Follow the steps in the guide to do that.

For the next two steps 4a and 5a, you can either use CustomPFD on your phone, or regedit with the "load hive" feature after mounting the phone as mass-storage on your PC. This is a bit too complicated for most people who are not into regedit, so I explain how to do that with CustomPFD instead. If you prefer to do with regedit, just follow the tutorial but use the values below as you do not want to impersonate the Lumia 950

4a. Use Windows Phone Application Deployment to deploy CustomPFD_0600. It will fail if you did not unlock the bootloader and root the device.

5a. Now with CustomPFD, go to HKLM\SYSTEM\Platform\DeviceTargetingInfo and edit those keys

"PhoneManufacturer"="HIGHSCREEN" (originally NOKIA)

"PhoneManufacturerModelName""="WinWin" (originally RM-877_nam_att_205 for AT&T, or RM-877_nam_usa_957 for unbranded or RM-877_nam_canada_235 for Telus)

"PhoneMobileOperatorName"="000-88" (originally LUS-CA or ATT-US)

We impersonate this model because it will only get WP8 GDR2, and nothing else. That's what we want.

Also, it is a good idea to add the following entries to blacklist extra+info and advanced info as indicated in http://xdaforums.com/showpost.php?p=64213053&postcount=304 to avoid the updates that block some rooting:

In HKLM\SOFTWARE\Microsoft\PackageManager\Blacklist, create DWORD32 entries containing "1" for extra&info, extra+info:

{2377fe1b-c10f-47da-92f3-fc517345a3c0}

{4c2aae0a-5e94-4d47-99e3-2608e34c536a}

and for advanced info:

{B6E3E590-9FA5-40C0-86AC-EF475DE98E88}

6a. Now disable root access. This is important, as the update will fail if you did not lock back the phone.

7a. Go to settings, check for updates again, and let the update run. When it is over, you will have 1537.148 also known as GDR2. Congratulations! You are unlikely to get any more update ever, but this is the best Windows Phone version ever made in my opinion.

If you want to restore the original regedit settings so that your 1020 is still recognized as a 1020, you need to use WPInternals to start in storage mode, then use regedit load hive. It is not possible to root the 1020 with WPInternals to use CustomPFD because the GDR2 version is not supported by WPInternals 1.2. Doing the regedit with loadhive is a bit complicated, so I assume you will not want do that. If you are a perfectionist, check the tutorial and restore the original PhoneManufacturer, PhoneManufacturerModelName and PhoneMobileOperatorName

2b. If you want W10M, keep going from here!

3b. Instead of following the guide, we will use the custom made ROM from http://www.windowsmania.pl/romy-315/ - obviously you must download it. The password is the website name

4b. Unlock the bootloader from WPInternal, then install this custom ROM. Tutorial on https://xdaforums.com/windows-10-mobile/th2-restone-windows-10-custom-roms-t3440144

5c. Glance will not work immediately. To fix it, follow the tutorial on https://xdaforums.com/windows-10-mobile/tutorial-restore-glance-windows-10-t3540571/page4

I love my 1020. It is a great phone giving me beautiful photos. If you read that far, you obviously also love your 1020 :) Whether you prefer to run it on WP8 or on W10M, you too should have the lastest software for your 1020.

If you find the guide helpful, and if you have a 1020 or 1520 in your drawer, I'd like to have it. I promise to give it a good loving home :) Even if it's dead, I would still like it, as I need parts because I plan to keep using my Windows Phones for a long long time!