Fixing CF-Auto-Root for the Nexus 6

[CleanSanchez]

tl;dr Use the fastboot executable that comes with adb-tools instead of the one that comes with CF-Auto-Root

I decided to upgrade the N6 to Marshmallow today, and everything was going smoothly until I tried to regain root with CF-Auto-Root. Every time I ran the .bat file I got he error:

...

We will now attempt to boot CF-Auto-Root. You should see a red Android on the
screen of your device in a minute, with scrolling white text on top of it.

downloading 'boot.img'...
FAILED (command write failed (Unknown error))
finished. total time: 5.004s

...

I hunted around google for a bit but couldn't find any real answer. I opened the .bat file to see what it was doing and maybe try to pinpoint the command that was failing. I saw that it was calling the fastboot that came in the CF-AutoRoot zip (tools\fastboot-windows.exe) On a hunch I copied in the fastboot.exe I had from adb-tools into the CF-AutoRoot directory, and changed all references of 'tools\fastboot-windows.exe' to 'fastboot.exe' in the .bat file.
I ran the .bat file again, and everything worked as it should. Booted into the OS and had root again.

Hopefully this can help someone in the future!

 

[simms22]

even better.. don't use toolkits to root, especially when you are not knowing much about the processes. learn to do it properly. its easier than using the toolkit for sure, and faster. if you know what you are doing already, then its fine to use a toolkit. but if you are clueless(like most that use toolkits), then learn the right way first, because toolkits mess up, and often.

 

[fast69mopar]

I have run into the same error while attempting CF Auto Root on my 3 day old Nexus 6. I dont know exactly how to move my fastboot.exe into the windows bat file but I am pretty sure I can figure it out with some reading and research. I agree with simms22 as well. I dont like using toolkits because I dont know what the toolkit is doing when it executes. I would rather perform the steps myself so I have a better understanding of what is happening during the process. I have a good understanding of adb and fastboot even though I am new to the Nexus 6. I am not new to Android though. @CleanSanchez, if there is any information you wouldnt mind passing on about how you modified the bat file I would appreciate it. Thanks for the quick little guide. I will get it figured out for sure. It may just take some time and some research. Thats all I have been doing for the first 3 days I have owned the device. I have read post after post and forum after forum here on XDA. I dont mind being a noob when it comes to a new device but Ill be damned if Im gonna make noob mistakes by getting in a hurry.

Edit:

I followed @CleanSanchez quick guide in the OP and wouldnt ya know, it worked for me too. I read a short Microsoft guide about editing Windows batch files and gave it a shot and it worked like a charm. Thanks for the guide.

 

[Plex.Le]

Rename the fastboot.exe is a bit easier than editing the bat. Thanks for the guide

 

[Borgov]

Some clarification for anyone needing more details.

Copy the fastboot.exe. file in the tools folder, into the zip CF-Auto-Root-shamu-shamu-nexus6.
Right click on the root-windows file and then click edit.
Change all 'tools\fastboot-windows.exe' to 'fastboot.exe' should be 6 lines of changes needed to be made
Make sure your Nexus 6 is in the bootloader
Click on fastboot.exe to root your phone

I must thank you @CleanSanchez because I got this phone a couple of days ago and this is only guide that actually worked. Hours spent got me continuously failing the fastboot windows. Even though it is years after the fact, you have my thanks.:good: