Help wanted: unable to downgrade back to 8.1 from win10

[niutu]

When I try to downgrade through Windows Device Recovery Tool (Lumia Recovery Tool isn't working), it always fails in the anti-theft phase. No matter how different USB ports I use, disable firewall and run the program as system administrator, take out microSD, reset the 830 to factory settings and then try to downgrade - it always fails during the anti-theft check...

I know MS introduced anti-theft protection during the 8.1 update 2 which I had prior to 10:
Windows Phone 8.1 Update 2 brings anti-theft Device Lock to Windows Phone - MSPoweruser
I did check my phone and it shouldn't have any 'reset protection'.

What I'm doing wrong and does anyone know any potential solutions?
Please share

 

[TechFreak1]

When I try to downgrade through Windows Device Recovery Tool (Lumia Recovery Tool isn't working), it always fails in the anti-theft phase. No matter how different USB ports I use, disable firewall and run the program as system administrator, take out microSD, reset the 830 to factory settings and then try to downgrade - it always fails during the anti-theft check...

I know MS introduced anti-theft protection during the 8.1 update 2 which I had prior to 10:
Windows Phone 8.1 Update 2 brings anti-theft Device Lock to Windows Phone - MSPoweruser
I did check my phone and it shouldn't have any 'reset protection'.

What I'm doing wrong and does anyone know any potential solutions?
Please share

Login into microsoft.com and check there if it's enabled.

 

[niutu]

Thanks, but already done that and reset protection is inactive.

 

[TechFreak1]

Thanks, but already done that and reset protection is inactive.

Not entirely sure what else you could try as I don't have an 830 to test .

 

[pankaj981]

When you say anti-theft protection what message does WDRT give you? Also is your 830 carrier variant?

 

[niutu]

When you say anti-theft protection what message does WDRT give you? Also is your 830 carrier variant?

Thanks for your input. First it starts by putting my 830 into writing mode, phone switches off and restarts, then comes the infamous phase of checking anti-theft - and the function immediately fails. Phone restarts again and WDRT just states function failed please try again. I've done this dozens of times and everytime I reach the same outcome.
Previously I upgraded 830 to 8.1 Update 2 before updating to Windows 10 Mobile. The anti-theft feature is somehow the culprit here, I don't have 'reset protection' or that sort of protection switched on.

My 830 is a Singaporean carrier variant (I guess so at least as it says CV MY SG), but I bought it in Finland and been using a Finnish sim without any problems.

 

[niutu]

Ok so I found a solution. In case someone is in the same situation and unable to roll back to 8.1 from 10:
Lumia 830, unable to downgrade to 8.1 - Microsoft Community

1. Turn off phone
2. Remove rear plastic, battery, SIM-card
3. Open Windows Device Recovery Tool
4. Connect the phone to PC with battery+sim still removed from phone
5. Press "My device is not detected", then "Lumia", and follow the instructions.

You may need to repeat this process a few times to get it working.

 

[myoujin]

I successfully revert back to windows 8.1 and then upgrade to 164. Last week use 14295.

At first I though weird when need open battery. But after test it flash without battery flash preparation is going smoothly.
I suggest you download first the firmware and try this method.