[TIPS] Stuck On FRF91? Want To Downgrade To Get Root? Click Here!

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Feb 6, 2010
Springfield, MA
Hello to Everyone!

If you are like I was, stuck on FRF91 without being able to downgrade to get root, or if you just want to be able to flash to any earlier version Nexus One rom, then this post is for you.

FRF91 does not allow you to flash to just any earlier version rom so for this tutorial, we will be using the EPE76 rom that I have already renamed to passimg.zip which allows us to bypass this limitation. The steps provided in this tutorial are all done on a stock t-mobile Nexus one with a locked bootloader, this is especially useful for people who wish to use the rooting method without unlocking the bootloader. If you already have an unlocked bootloader, there is no reason to follow this guide.

"Update" confirmed to also work on at&t nexus one

Notice: after you do this you will have to redownload your apps.


1. Transfer the provided passimg.zip file to the root of your sd card.

2. Power down your phone.

3. Hold down the Volume Down button as you power your phone back on.

4. A screen should appear showing your phone’s system searching for various files. This will take up to 2 minutes.

5. The phone will ask you if you want to start the update. Press the Volume Up button to start the update.

6. If you followed these steps correctly, Congratulations, you are now on stock EPE76 Android 2.1 and able to flash to any official Nexus One rom that has been released.

If this guide helped you please let people know, the more posts there are, the more comfortable other people will feel to follow this guide.
Last edited:


Feb 6, 2010
Springfield, MA
@ Amdathlonuk

If you received that error, then it was not done correctly. I downgraded from FRF91 two times before posting the tutorial and it worked both times, please make sure to follow the guide 100% exactly as posted or it won't work. Thanks.


Senior Member
Dec 1, 2009


New member
Jul 4, 2010
OMG, I was stuck on frf91 for the past 3 days after manually updating like an idiot. You saved me from a lot of headaches. Very easy tutorial. Donation on the way. Thank You.


Feb 6, 2010
Springfield, MA
I don't think that is the problem because I myself used frf85b universal after doing the steps posted above and then rooted successfully following the how to root nexus one without unlocking the bootlowder tutorial.

Sent from my Nexus One using XDA App


Mar 27, 2009
Could I get a download link to the universal 85b zip to do this please. The Google download is not working it shows that the file is not found. Would appreciate it very much


Senior Member
Apr 16, 2007
If his guide helped you, please consider buying him a beer.

Why ?

Is he ( juan413 ) a dev or something, why ask for money for this "guide" ..?

and @ebuyer27 .. LOL ?

Join Date
4th July 2010
Total Posts

and donation "on the way" ... Yeah Right ! ! ! Maybe he "donated" himself ... LMAO


donation goes to > [[email protected][/email]

Watch out guys ! ! !
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  • 1
    i was able to downgrade no problem now it will not let me upgrade to 85b or other 2.2 verisons it says

    e: cant open/ cache/recovery/command
    E: failed to open /sdcard/update.zip (no such file or directory)
    E:signature verification failed

    Are you using the universal 85b?
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