Black Boot Screen with GT 120 & LG 31MU97

Discussion in 'Mac Pro' started by serge-m, Feb 25, 2016.

  1. serge-m macrumors newbie


    Feb 25, 2016
    Hi Folks,

    thirst thread here :)

    As you can see at my signature, I have a 4K display, that normally runs by a GTX 980 (non Efi).
    With that card, I have a black booting screen as expected and after that the desktop at 4K.

    To have finally a boot screen (for updates and those stuff), I bought a GT 120 Mac Edition.
    So I removed the GTX 980, I put in the GT 120 in Slot 1 of my Mac Pro, plugged in the cable to the miniDP of the card and to the LG monitor I used the DP.

    Then I reboot...
    And: black screen...

    I tried Slot 2.
    I tried to lower the resolution (e.g. 1920x1080).
    I tried it with OSX Driver and Nvidia Driver separately.
    I did a PRAM reset. 3 times.

    Still no boot screen.

    I have the latest update of El Capitan. And the latest Nvidia Driver (346.03.05f02)

    Can anybody help me out of this...?

    That would be nämlich ziemlich great o_O
  2. scott.n macrumors 6502

    Dec 17, 2010
    Do you eventually see the desktop with your GT 120? You should.

    If your display has a setting to change the refresh rate to 30Hz, then I would try that. Alternatively, if you have an mDP-HDMI adapter, connect the display to your GT 120 using it (which should force 30Hz).

    The GT 120 will definitely run 4K at 30Hz. I've done it, but I don't recall if I saw a boot screen. Some Mac cards just won't show a boot screen on a 4K display. But understand that you don't need a boot screen for the updates that you mention. You can still boot into your desktop with the GT 120, install Nvidia drivers, and then reinstall your 980.
  3. serge-m, Feb 25, 2016
    Last edited: Feb 25, 2016

    serge-m thread starter macrumors newbie


    Feb 25, 2016
    Hi Scott,

    thanks for the reply !
    Yes, I see the desktop at the end.
    I could not find a setting to set the monitor to 30Hz. Also, I only have a mDP-to-DP cable, but considering to buy a DVI-to-mDP cable or adapter.
    Or is your option the better idea ?

    Do I really don't need the boot screen ?
    Last time, then updating to El Capitan, the LG display stayed black at the end of the update. I ran the update at 4K with the 980. And I could not see the last update procedures...
    I had to force quit the Mac, remove the card and put an older one (GTX 480) in it and then the Mac showed me the final update step (where I just had to click in some fields to confirm...).

    Putting the 480 in the Mac forced the system to run at a lower resolution. Maybe, before running an update, I should set the resolution from 4K to something about 3200 or so. Maybe the update won't show screens at 4K...(?).

    What about a firmware update for my 2 Samsung 840 Pro SSD's ?
    Dont I need a graphic card, that can show the boot screen, to run such an update (Samsung demands this iso USB stick or iso CD to boot with in order to get this firmware update to run) ?
  4. scott.n macrumors 6502

    Dec 17, 2010
    You definitely do not need a boot screen for updating Mac OS. But you don't need to switch cards, either, if you have another computer (or even an iPhone or iPad) that can screen-share/VNC into your Mac Pro. See the NVIDIA card wiki at the top of this forum, especially the section about setting boot-args.

    Firmware updates for things like your SSDs are a little different. You probably do need full EFI support in that case.

    An mDP-HDMI adapter would be more likely to work than DVI-mDP, but I don't know for certain.
  5. serge-m thread starter macrumors newbie


    Feb 25, 2016
    Thank you.

    I see...
    I will try this mDP-HDMI adapter ! And also have a look at this VNC thing with my iPhone or iPad.

    But just one question regarding the update situation:
    as I mentioned before, during the update procedure, I saw just black at the end of that update and so could not see those confirm buttons (I had the 980 in).
    After putting in the 480, the Mac shows the screen - with a lower resolution !
    I thought, ok, if I do an update next time with the 980, I just set the card to a lower resolution, so that I see all of the update screens.
    Is that the case ? Should I go to a lower resolution than 4K in my case, so that OSX will show me the whole update procedures ? (maybe the update procedure needs a lower screen resolution)
  6. scott.n macrumors 6502

    Dec 17, 2010
    Your problem with the OS update is not related to the screen resolution. Maxwell cards (like your 980) will prevent the Mac from booting unless Nvidia drivers are installed or you set boot-args="nv_disable=1" first.

    Because the Nvidia drivers are tied to a specific OS build number, when you update the OS, the version that you have installed will no longer work.

    Besides the sticky at the top of this forum, I'd recommend reading through this (much shorter) thread:

    In brief, this is what you need to do when doing an OS update:
    1. Download OS update
    2. Enter sudo nvram boot-args="nv_disable=1" in Terminal
    3. Reboot to install update
    4. Screen share into machine and log on
    5. Download updated web drivers
    6. Enter sudo nvram boot-args="nvda_drv=1" in Terminal
    7. Reboot to install new web drivers

    For step 4, you could substitute "install GT 120" for screen sharing. Or you could leave both the GT 120 and GTX 980 installed, and switch your input to the former. But even with both cards installed, you would still need to set boot-args as described.
    --- Post Merged, Feb 25, 2016 ---
    And by the way, as far as screen sharing into your Mac Pro goes, this needs to be set up by turning on "Screen Sharing" in the Sharing prefpane in System Preferences. Third-party apps like Screens, etc, won't work for this purpose.
  7. MacVidCards Suspended

    Nov 17, 2008
    Hollywood, CA
    Or get the 980 flashed and solve all of these problems.

    Selling the 120 & 480 would probably cover it, esp if 480 is a Mac one
  8. serge-m, Feb 26, 2016
    Last edited: Feb 26, 2016

    serge-m thread starter macrumors newbie


    Feb 25, 2016

    Hey Scott,

    wow, thats a kind of to-do-list just to have a viewable update ;)
    But I know these issues using PC cards and so: big thank you for your support !
    I will check out all your suggestions beginning with the adapter.

    All the best

    --- Post Merged, Feb 26, 2016 ---
    Ha, Ha :D - that IS the best way, I know.
    A little too expensive sending my card from Germany with all the fee in between... - but definitely the best way !

    I had some contact with a guy here in Germany, who offers this service too: flashing PC cards for Macs.
    I wanted to maybe contact him again, but then I looked around on your blog just some minutes ago, I read, that there are "copy-cats" of your hard work around. And also a guy in Germany...
    I'm not sure, if this is the same guy, but he would flash my 980 for 325,- €...
    Do you also have collaborations here in Germany, so that I and other users can trustful use their services ?
  9. MacVidCards Suspended

    Nov 17, 2008
    Hollywood, CA
    Nope, guy in Germany isn't legit. Do have a partner in UK who just started up.
  10. bwinter88, Sep 28, 2018
    Last edited: Sep 28, 2018

    bwinter88 macrumors newbie

    Jul 20, 2012
    This might be too little, too late, but I have this monitor and graphics card combo as well.

    Firstly, you need to do an SMC and PRAM reset when you switch the cards. Unplug your mac for 15 seconds. Then boot up and hold CMD+Option+P+R until you hear the THIRD chime. Make sure you LOG IN before restarting again.


    The LG monitor needs to be ON and not on STANDBY when your mac boots up.

    And DisplayPort 1.2 should be Disabled in the monitor's options menu.

    It seems the monitor needs to be "awake" and "ready to receive" a signal for the display to appear.

    To do so, keep hitting the MENU button to keep the monitor "awake" while the Mac boots up. It should "catch" the boot screen.

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