cannot reset nvram (dead firmware battery?)

Discussion in 'MacBook Pro' started by dophineh, Aug 28, 2016.

  1. dophineh macrumors member

    dophineh

    Joined:
    Jan 29, 2009
    Location:
    California
    #1
    I have a mid '14 MacBook Pro 15" that will not boot due to a (1) typo I made in the nvram's boot-args, and (2) inability to reset the nvram. I suspect this is because my machine has a dead firmware battery, which it may have always had- I've always noticed that exhausting the main battery would fudge up the operating system's time and date upon next start up.


    Troubleshooting so far:
    Regular boot attempts and safemode boot results in a flashing "?" folder.

    Recovery mode boot attempt (requires my firmware password) results in a slashed circle and an endless cycle of verbose lines starting with "IOHDIXController: NOTE: administrator is creating non-ejectable disk image" and ending with "cannot mount root, errno = 19". See included picture of screen for the other 6 lines.

    [​IMG]

    I've also tried to reset the SMC (control-option-shift then power) as well as resetting the firmware/nvram specifically.

    The specific typo I made to the nvram's boot-args:
    (But this shouldn't matter, I should be able to reset the nvram and erase the nonsense, correct?)
    Inside of nvram's boot-args I set 'rd=disk1s1' which is an un-bootable partition- essentially forcing an un-bootable start up disk.


    Also, note: I have a firmware password set which shouldn't make a difference as I remember the password.

    [​IMG]



    All in all, I'm thinking it's a dead firmware battery which was long overdue for repair. What else could it be?
     
  2. DeltaMac macrumors G3

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #2
    What happens when you try a PRAM reset?
    Hold Option-Command-P and R. Press and release the power button.
    You should hear a boot chime. Continue to hold the same 4 keys until you hear the boot chime two more times, then release the keys.
    THAT should reset your bungled NVRAM command, regardless of the state of the backup battery.

    You may have a really-messed up partition map on your storage.
    This would be a great time to have a USB bootable installer.
    You could also try booting to Internet recovery (restart, holding Option-Command-R). You SHOULD see a spinning globe as your MBPro connects to Apple's servers through your internet connection.
    Either the external bootable installer, or the internet recovery would also give you the utility that will clear your firmware password.
    Yes, it shouldn't make a difference, but it may be interfering with your capability to easily reset your NVRAM.
    Clear the firmware password, then do another PRAM reset.
    If that clears out those boot error messages, I suggest that you reinstall OS X to make sure that all is good with your system software.
     
  3. dophineh thread starter macrumors member

    dophineh

    Joined:
    Jan 29, 2009
    Location:
    California
    #3
    I have not been able to get the double chime PRAM reset to work. I've tried various different timings, and even tried using the right option key, as well as tried it right after an SMC reset, but it still stubbornly refuses to clear out it's firmware mind.

    I've tried booting on a SD card as well as the network boot. Neither seem to be able to override the boot-args in the nvram.

    With the network boot for example, after holding down the Option-Command-R combo, I get prompted for my firmware password which I then enter successfully and it continues to the spinning globe where I choose a wifi network and proceed. Once that progress bar completes, the verbose log screen appears and it then forgets anything it just learned and goes right away and attempts to boot 'disk1s1' and ends in the same endless "cannot mount root, errno = 19" cycle.

    My theory (since I suspect the firmware battery was already kaputt) is that the firmware battery is needed to make changes to the firmware. Without it, it stays firm so to speak.

    You would think the main battery would be able to write to the firmware too, but perhaps not until after single-user mode is exited?? Uhh...

    Note: The verbose clause is also in the nvram's apparently permanent boot-args as '-s'
     
  4. DeltaMac macrumors G3

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #4
    Can you run diagnostics?
    (Restart, hold the D key)

    Have you tried disconnecting the main battery, then try a reset with only the power adapter attached?
     
  5. Fishrrman macrumors G5

    Fishrrman

    Joined:
    Feb 20, 2009
    #5
    Something tells me that the firmware battery (PRAM) has a life expectancy of more than just two years.

    Messing with nvram ain't a good thing to do.

    Perhaps it's time for a trip to the nearest Apple Store genius bar...
     
  6. dophineh thread starter macrumors member

    dophineh

    Joined:
    Jan 29, 2009
    Location:
    California
    #6
    No luck with D key startup.

    I have not disconnected the main battery. It is internal on this generation of MBP, and for the record, I have not opened/unscrewed the case (yet).
    --- Post Merged, Aug 29, 2016 ---
    I seem to recall noticing the OS clock would lose itself after I exhausted the main battery right from the very beginning, so perhaps it shipped with a dead firmware battery... or... maybe I called it a bad name once and it was mad at me and the IOHDIX controller went rogue and fried the logic board... please jees allow it to only be a faulty firmware battery.

    I mess with my stuff, always have, and I've learned alot of good, useful skills and tricks. This is the first time I've bricked a mac. I have much to learn... :p
     
  7. T5BRICK macrumors G3

    T5BRICK

    Joined:
    Aug 3, 2006
    Location:
    Oregon
    #7
    Do current Macs even have a separate firmware battery? I thought that went away when Apple moved to Intel.
     
  8. JTToft macrumors 68040

    Joined:
    Apr 27, 2010
    Location:
    Aarhus, Denmark
    #8
    - That's my understanding as well. At least as far as portables go. The information I've been able to find is vague and conflicting on it, though.
     
  9. DeltaMac macrumors G3

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #9
    I'm pretty sure that there is just a dedicated cap that keeps firmware settings intact. Not an item that you could call a "battery", and not a replaceable item, in any case.
    The OP should not be losing time & date, however.
    And, it's probably the same reason that OP can't boot to Diagnostics.
    @dophineh, you should get your MBPro to Apple service, or call AppleCare. Try to avoid mentioning that you screwed around with your NVRAM settings (should not make a difference, but I may be wrong about that)
    Or just take to an Apple store, where they can run their own test.
    If you have AppleCare extended warranty, that should apply. Even if you are out of warranty, you should at least get a good idea about what is needed for a fix.
    If Apple wants to charge you for a repair, ask about a "flat-rate repair", where your Mac is shipped to a central repair center. Assuming there is no accidental damage, you will get your Macbook Pro back in like-new condition, replacing whatever parts are needed, all for a flat-rate maximum fee of about $275, IIRC
     
  10. T5BRICK macrumors G3

    T5BRICK

    Joined:
    Aug 3, 2006
    Location:
    Oregon
    #10
    I only mentioned it because the PPC based macs actually had a separate battery for the PRAM.
     
  11. dophineh thread starter macrumors member

    dophineh

    Joined:
    Jan 29, 2009
    Location:
    California
    #11
    They absolutely have a separate firmware battery. Because what it is really, is a clock battery. Without it, how would the machine keep track of time when the main power source is exhausted?
    --- Post Merged, Aug 30, 2016 ---
    UPDATE:
    So I made an appearance at the genius bar. I was not shy about any of the details including the very line I entered into the nvram's boot-args from a singler-user command prompt. I offered to write down my firmware password for them but they said they did not need it and instead had me enter it each time it was needed :)

    They performed all the basic troubleshooting as I twiddled my thumbs. They connected my machine to an on-site diagnostics server and ran hardware diagnostics which it passed all of. Then after failing to launch their server's OSX 10.11 (it ignored and still attempted to boot to the nonsense drive I typed in to the nvram "disk1s1") they took it into the back room to perform a hard-power-cycle- that is, open up the case and disconnect the main battery- something they later promised me would 'void the warranty' or rather since it is already out of warranty- would make it un-serviceable.

    After she returned from the back room with my machine, it still would not boot. No progress had been made. She excused herself temporarily to help some other customers and was so kind to allow me to use their server diagnostics tool hookups with the "Customer Facing Quiet Mode" disabled. I was kinda impressed.

    With the diagnostics hooked up, there were about 12 different network bootable drives displaying next to my two hard drive partitions. Some of them were 10.9, 10.10, and 10.11 versions of fresh install, recovery, and diagnostics. One was simply named "serial".

    The first one I booted on (and I forget which one I even choose) lead me into a screen that in an accusing tone told me that if I had forgotten my filevault passwords I could reset them and did not give me any other options. So I held down the power button and booted to another partition...

    Finally after a bunch of boots of various partitions from their server (which I noticed all sorts of weird details including seeing the verbose log screen in what must have been 4x retina mode- that is, really tiny text.) we booted on a install partition, and had the good fortune to happen upon the firmware password tool which allowed me to disable the firmware password. So for the 1,000 within the hour, and the last time EVER perhaps, I typed in my firmware password and disabled it.

    We then attempted the firmware reset. And for the first time, I heard the double chime that I've read about. And I was able to boot up. My machine was bricked no longer. Success!!!

    Now, the issue may remain... that the clock goes back to the year 1865 or 1970 or whatever if I exhaust the main battery.

    Apple will not change this secret battery without swapping out the entire logic board for a flat rate of 310$. However, I noted that disconnecting the battery (in the back room which I did not see) did not fuzzle the clock when I was finally able to boot.
     
  12. T5BRICK macrumors G3

    T5BRICK

    Joined:
    Aug 3, 2006
    Location:
    Oregon
    #12
    From what I understand, the unibody Macs do not have a PRAM battery or clock battery anymore. Either they just use the main battery and/or a capacitor to keep the clock going. The capacitor likely acts as a battery, yes, but it isn't actually a battery and it shouldn't wear out.

    https://www.ifixit.com/Answers/View/115589/PRAM+battery,+can+I+replace+it+myself
    https://discussions.apple.com/thread/3423099
    https://discussions.apple.com/thread/4890944

    On old iBooks and PowerBooks, and early MacBooks and MacBook Pros, they had a seperate battery that could be removed and replaced.

    https://www.ifixit.com/Guide/MacBook+Core+Duo+PRAM+Battery+Replacement/297
     
  13. dophineh thread starter macrumors member

    dophineh

    Joined:
    Jan 29, 2009
    Location:
    California
    #13
    Yes, in that case. My understanding of a capacitor is that it is a 'battery' in that in stores a charge.

    So it is essentially a rechargeable 'battery', even if it is not a traditional chemical based battery.

    Therefore, it can be completely exhausted if it cannot recharge from the primary power src.

    This would explain why the clock has lost track in the past but did not lose track when the main battery was disconnected yesterday.

    So in the end, the culprit here was the firmware password combined with me disabling any remote overrides by apple.

    Lesson learned: do not use a firmware password when you are learning nvram syntax. :D
    --- Post Merged, Aug 30, 2016 ---
    Apparently it is the case that you cannot reset the firmware while there is a firmware password in place.
     

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