Can't Boot back to Mac

Once I am in Windows, I reboot and it keeps booting Windows. If I zap PRAM I can go back to Mac, but then have to disable SIP. Is there something I can check to see why it won’t boot back to Mac?
I keep selecting the Mac volume in startup disk, but when I reopen it, neither is selected.

The currently selected startup disk is stored in NVRAM. You can view it by running:

nvram -p

You should see efi-boot-device-data in nvram. After you zap the PRAM, it should clear out all those values. For some reason, startup disk does not sound like it is setting that value.


Thanks Tim,

Running nvram -p give me

bluetoothInternalControllerInfo %15%82%ac%05%00%00%11Zx%ca9%ca%00%19
fmm-computer-name MacPro
efi-boot-device IOMatchIOProviderClassIOMediaIOPropertyMatchUUID38B9085C-C086-4BD1-B35A-0E1C665CC76ABLLastBSDNamedisk3s2IOEFIDevicePathTypeMediaFilePathPath\21725BEA-C027-4119-B052-8CFFC27B0165\System\Library\CoreServices\boot.efi%00
prev-lang:kbd en:0
bluetoothActiveControllerInfo %15%82%ac%05%00%00%00%00%11Zx%ca9%ca%00%19
SystemAudioVolumeDB %fb
SystemAudioVolume ;
efi-boot-device-data %02%01%0c%00%d0A%03%0a%00%00%00%00%01%01%06%00%00%01%01%01%06%00%00%00%01%01%06%00%00%04%01%01%06%00%00%00%03%12%0a%00%01%00%00%00%00%00%04%01*%00%02%00%00%00(@%06%00%00%00%00%00`-jt%00%00%00%00%f9Q%90x%88?%b5M%bf%f2+%ba@T:%a2%02%02%04%03$%00%f7%fct%be

Once the PRAM is reset, it boots to the mac and then to switch, I have to disable SIP, etc. Then I can use Boot Runner to switch to Windows. Once there it will only reboot into Windows, only way back to Mac is reset PRAM. Any thoughts you might have I can check?

Thanks again!

I think I misunderstood your question. Zapping the PRAM definitely does re-enable NVRAM protection for Boot Runner and that prevents Boot Runner from selecting the drive. That is expected and there is no current way around it.