[OnePlus 10T 5G] beatbreakee:
so after doing some research i have found 2 things... 1. Oppo has ppl watching this thread and has made some alterations to the files that come from their server... these are the only 3 i had original copies of but of those 3 ALL of them had a minor difference and all were modified right after I revealed that i had success in converting my 2419 to a 2415. Once i stated that i was able to move to ANY region using my method, SOMETHING very small was changed in the files, and that is the reason the 2417 OTA fails to load in Local Updater... look at the attached pic. View attachment 5766339

So this is obvious that they are onto us and this is a concern to them. You should still be able to Downgrade with any region that has an Android 13 Beta. The technique works perfectly as long as you have a full version of Android in between.... AKA 12 to 13, and 13 back down to 12. And because of the new links in the OP, you can use local update to roll back to 2413 or 2415 ... I do believe that a 2417 beta is imminent and as such there will have to be a 2417 rollback released with it. There is still no danger with using this method, as you see because if the file is incompatible. local updater will fail to populate it!

Now for the second thing. OPPO used to have a special function in the Engineering Mode, which when activated would re-enable Fastboot Mode on the devices temporarily. This function is still alive in these devices today, only it has been hidden away deeper. This was confirmed to me after another grueling 3 hr chat with OnePlus technicians. I was told, "Sir we do not have access to the program you are asking about. The MSM Tool is completely maintained and controlled by OPPO division, and while yes we are under their ownership, there remains 2 different divisions in our company" ... 1st tech ..... "Sir you would need to enable fastboot mode so that you can flash the original firmware to your device, if it is failing to boot. You need to enter "Factory Mode" and input the locking code which is calculated from your device Imei. Once you have entered the code, you will be instantly rebooted into fastboot mode, and there you will be able to flash the signed firmware to it. Do not attempt to flash unsigned firmware as it will fail if your device comes with a locked bootloader." ..... 2nd tech......

This is not FastbootD he is talking about, because in FastbootD you do not need "Factory Mode" to enter it, and a little bit further research found this post which almost exactly matches what the tech told me!

Factory Mode Unlock

Of course the same way that Oppo decided to interfere with me, they also interfered with this method. They went and simply unlocked engineering mode completely in our devices, which made the screen where you enter the code, vanish. But i guarantee you, that based on some digging into the system files that our devices have running, i found several processes mentioning privileged processes that have simple flags that are called when "pre-boot" functions are initiated. Now in YEARS of time that OPPO has had to deal with the programming these devices they have never managed to actually eliminate "Fastboot Mode". They just become sneakier in hiding it behind user accessible operations. I am fully confident that the same thing applies here. While i dont have all the answers, i implore you all to apply the knowledge i have given and help find just where it is hidden in ours.

To call Engineering Mode on our phones, the code was changed to:

*#899*

Maybe the unlock screen has been hidden in here under a different label... maybe they created a new dialer code, but make no mistake, OPPO must have a need for this mode for repairing our phones otherwise they would eliminate it completely. Oppo is a 2-bit chinese company who is too cheap to design a new OS, and therefore somewhere, there is going to be a method to gain what were looking for. That is all i have for now.... but i am still digging. ( i have managed to get an additional 2 weeks to hold onto the 10t before i have to drop it into the return box and hand it over. So any ideas that you come up with, you DO NOT have to risk your personal devices! I can try ANYTHING on mine with absolutely ZERO ****s to give, as to it getting bricked! BRAINSTORM PPL! let me know what you come up with and i will try it!)