[ONE Q&A, Help & Troubleshooting] ninjawulf98:
So i have both the short story with some important explanation and the long story on what I've already tried.

Short story

So my dad bought a oneplus one 16GB from someone and the phone has a bootloop when you try the boot into the system.

I tried to unlock the bootloader, but it runned the command and it just reboots to recovery and the bootloader is still locked.

Also the tamperflag is true so that means that the bootloader has already been unlocked and is relocked.

I can't also boot from a custom recovery image because the bootloader is locked (I think it can with CM11S).

Rom: I guess it is CM12S (with the blinking Cyanogen logo at startup).

Recovery: probably the recovery from CM12S (Cyanogen recovery as text and it is a touch recovery).

Long story

So I am going to tell you my story.

My dad bought an oneplus one (16GB) from someone that had a boot loop at startup.

When he told me that I just thought that it was going to be pretty easy to fix: unlock bootloader, flash custom recovery and install a custom rom.

Now, it didn’t roll out as we both expected.

When I unlocked the bootloader it told me after 10 seconds that it was OK.

Pretty weird was that it took so long.

After some research I found that you need to reboot from the rom with adb and that you then can unlock the bootloader. On all my other devices I did that, but now I couldn’t because I wasn’t able to boot inside the rom.

After I “successfully” unlocked the bootloader I did the command “fastboot oem device-info” and it told me that the bootloader was still locked but it was tampered.

I tried after that to boot from a TWRP recovery image but i wasn't able to because the bootloader was locked.

After some research I came at a post on the oneplus forum with a guy that approximately had the same issue except that I can still go into recovery.

I founded this post.

And I first wanted to see if I couldn’t go into recovery and sideload a zip that is signed. That was signed in this thread.

As it expected because I didn’t had a custom recovery it didn’t worked and also I used this tool for adb and fastboot.

I didn’t give up by that one so easily so I tried it with this to sideload the files and I renamed it this time to update.zip. Again as expected an error but this time it was another error.

There came a bunch of errors on the phone especially cache errors and one that said that I had an outdated ADB (at least version 1.0.32).

Weirdly enough I had version 1.0.32 .

And now it tried the trick they told me here.

From the thread for windows 7 and 8 here.

I first did this without “erasing the bootloader”.

I tried this both on windows 8.1 and on windows xp with both administrator rights and I switched between 3 cables each time.

As you see in the attached zip, I correctly installed the driver, this was also the fact for the pc with windows xp.

I also verified the files but there were some that failed (also in the pictures).

It flashes the file 8974_msimage.mbn and then the phone shuts down. I tried this at least three times for each computer.

Then I founded this thread.

And tried this also and exactly the same problem as with color.

Then I tried the same with erasing the bootloader and it had the same issue and I couldn’t erase the bootloader doing to that my partition table doesn’t exist(also in the pictures).

The only thing that I only think that I can do is with a flash tool that uses also the above method but I don’t find any with that I know how to use it.

Any help is appreciated.

Ps: I attached a zip file with some pictures to make it more clear and understandable and i am also dutch, so sorry if my English is bad.