Cannot unlock bootloader
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Cannot unlock bootloader
Hi everyone,
I'm desperately looking for some tips to solve my problem.
I have a Lumia 950 no-brand, which I unlocked a week ago with wpInternals and everything seems good.
Unfortunately I could not use woadeployer since i got stuck in some error after converting windows image, so I decided to start over cause I thought I was sloppy following the tutorial. I restored original bootloader, flashed the original FFU with wpInternals and my windows mobile worked smoothly.
Here comes the problem, I cannot unlock bootloader anymore since I get BAD GPT error and I have no clue how to fix it.
I tried to restore 4-5 different FFUs, but nothing changes
Can anyone help me?
Thanks
I'm desperately looking for some tips to solve my problem.
I have a Lumia 950 no-brand, which I unlocked a week ago with wpInternals and everything seems good.
Unfortunately I could not use woadeployer since i got stuck in some error after converting windows image, so I decided to start over cause I thought I was sloppy following the tutorial. I restored original bootloader, flashed the original FFU with wpInternals and my windows mobile worked smoothly.
Here comes the problem, I cannot unlock bootloader anymore since I get BAD GPT error and I have no clue how to fix it.
I tried to restore 4-5 different FFUs, but nothing changes
Can anyone help me?
Thanks
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Re: Cannot unlock bootloader
Hello fabriloddo!
Welcome to our Windows on ARM community
Let me try helping you by finding out more about your situation.
1. Can you boot into Windows 10 Mobile? (BAD GPT seems severe)
2. In which step do you get BAD GPT? Does wpinternals report it or do you read it from the Lumia 950 screen?
3. Have you tried the Windows Device Recovery Tool from Microsoft?
You might have encountered the Samsung flash-memory bug. But I pray that you didn't. Since I never did myself I cannot speak for the symptoms.
Welcome to our Windows on ARM community

Let me try helping you by finding out more about your situation.
1. Can you boot into Windows 10 Mobile? (BAD GPT seems severe)
2. In which step do you get BAD GPT? Does wpinternals report it or do you read it from the Lumia 950 screen?
3. Have you tried the Windows Device Recovery Tool from Microsoft?
You might have encountered the Samsung flash-memory bug. But I pray that you didn't. Since I never did myself I cannot speak for the symptoms.
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Me on OSDN.net: https://osdn.net/users/quiret/
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- x 2
Re: Cannot unlock bootloader
Thank you for your reply:
So, here's the thing:
1. Can you boot into Windows 10 Mobile?
Yes, phone seems working good (it's a spare old phone so i didn't try much, but it boots and load default apps.)
2. In which step do you get BAD GPT? Does wpinternals report it or do you read it from the Lumia 950 screen?
Error occurs just upon clicking on "unlock" button, after choosing ffu and emergency files in Unlock Bootload section.
3. Have you tried the Windows Device Recovery Tool from Microsoft?
I actually tried lot of times either with WDRT, and WPi. result is the same.
Please check attachments
thanks for your help
So, here's the thing:
1. Can you boot into Windows 10 Mobile?
Yes, phone seems working good (it's a spare old phone so i didn't try much, but it boots and load default apps.)
2. In which step do you get BAD GPT? Does wpinternals report it or do you read it from the Lumia 950 screen?
Error occurs just upon clicking on "unlock" button, after choosing ffu and emergency files in Unlock Bootload section.
3. Have you tried the Windows Device Recovery Tool from Microsoft?
I actually tried lot of times either with WDRT, and WPi. result is the same.
Please check attachments
thanks for your help
- Attachments
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- A.jpg (49.89 KiB) Viewed 9709 times
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- B.jpg (4.13 KiB) Viewed 9709 times
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Re: Cannot unlock bootloader
After investigating the source code of wpinternals 2.8 the error could stem from two sources:
1) the GPT that wpinternals receives from your phone is in an unknown format or damaged (line 2182 of LumiaV2UnlockBootViewModel.cs)
2) the GPT inside of your FFU files has an incorrect format or is damaged (line 142 of FFU.cs, line 2095 of LumiaV2UnlockBootViewModel.cs)
You can detect 2) by checking the wpinternals log file. If you cannot find the text "Assembling data for unlock" then your FFU file is faulty.
What to do if your FFU file is faulty?
1) check that your harddrive storage medium is working properly. calculate the checksum of the FFU file and compare it with a known correct checksum.
2) check whether the download of your FFU file was faulty (bad internet connection, etc). verification is possible using the same method as by 1).
1) the GPT that wpinternals receives from your phone is in an unknown format or damaged (line 2182 of LumiaV2UnlockBootViewModel.cs)
2) the GPT inside of your FFU files has an incorrect format or is damaged (line 142 of FFU.cs, line 2095 of LumiaV2UnlockBootViewModel.cs)
You can detect 2) by checking the wpinternals log file. If you cannot find the text "Assembling data for unlock" then your FFU file is faulty.
What to do if your FFU file is faulty?
1) check that your harddrive storage medium is working properly. calculate the checksum of the FFU file and compare it with a known correct checksum.
2) check whether the download of your FFU file was faulty (bad internet connection, etc). verification is possible using the same method as by 1).
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Me on OSDN.net: https://osdn.net/users/quiret/
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- x 2
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- Posts: 5
- Joined: Fri Dec 06, 2019 1:31 pm
- x 2
Re: Cannot unlock bootloader
well, apparently I managed to complete all the process smoothly.
I can't tell for sure but I think WPi wasn't properly downloading FFUs (or overwriting downloaded ones) .
I started from scratch, brutally deleting wpi Repository folder from my hard drive, and everything worked.
I managed to install a dual boot with latest w10 19041.1 and w10m
Camera button is not working yet, and also phone camera is not detected but hopefully it'll work in the future.
I still have to figure out how to set up a confortable set-up to work with tablet mode and screen zoom %,
To be honest, I don't know which is the best w10 version to deploy at the moment, but I guess I'll figure it out.
I'm pretty happy for the result right now.
Thank you for the tips

I can't tell for sure but I think WPi wasn't properly downloading FFUs (or overwriting downloaded ones) .
I started from scratch, brutally deleting wpi Repository folder from my hard drive, and everything worked.

I managed to install a dual boot with latest w10 19041.1 and w10m
Camera button is not working yet, and also phone camera is not detected but hopefully it'll work in the future.
I still have to figure out how to set up a confortable set-up to work with tablet mode and screen zoom %,
To be honest, I don't know which is the best w10 version to deploy at the moment, but I guess I'll figure it out.
I'm pretty happy for the result right now.
Thank you for the tips

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Re: Cannot unlock bootloader
You're welcome!fabriloddo wrote: ↑Wed Dec 11, 2019 11:24 amI'm pretty happy for the result right now.
Thank you for the tips![]()

I will be testing the Lumia 950 XL with W10ARM64 once my dad actually passes it to me. (he actually likes his Lumia phone)
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Me on OSDN.net: https://osdn.net/users/quiret/
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Re: Cannot unlock bootloader
I guess it'll be soon if he's a whatsapp user. App will no longer work after 31st december..
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