Quick steps:
If you got this error:
Persistent boot order cannot be changed during POST
Make sure that the server was powered off first!
First, look at the partition table:
~ $ diskutil list /dev/disk0 (internal, physical): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *1.0 TB disk0 1: EFI EFI 209.7 MB disk0s1 2: Apple_CoreStorage Macintosh HD 999.7 GB disk0s2 3: Apple_Boot Recovery HD 650.0 MB disk0s3 /dev/disk1 (internal, virtual): #: TYPE NAME SIZE IDENTIFIER 0: Apple_HFS Macintosh HD +999.3 GB disk1 Logical Volume on disk0s2 03C9C615-4A75-4F55-BFE2-3D1EFAD7519E Unlocked Encrypted /dev/disk2 (external, physical): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *7.8 GB disk2 1: EFI EFI 209.7 MB disk2s1 2: Microsoft Basic Data NCS1002 7.6 GB disk2s2 |
In my case, the USB drive is /dev/disk2.
I want to reformat the device to an MBR-formatted FAT32 partition. To do that, run this command:
sudo diskutil eraseDisk FAT32 {NAME} MBRFormat /dev/disk2 |
where NAME is the name you want to give to the disk.
For example:
~ $ sudo diskutil eraseDisk FAT32 NCS1002 MBRFormat /dev/disk2 Password: Started erase on disk2 Unmounting disk Creating the partition map Waiting for the disks to reappear Formatting disk2s1 as MS-DOS (FAT32) with name NCS1002 512 bytes per physical sector /dev/rdisk2s1: 15210832 sectors in 1901354 FAT32 clusters (4096 bytes/cluster) bps=512 spc=8 res=32 nft=2 mid=0xf8 spt=32 hds=255 hid=2 drv=0x80 bsec=15240574 bspf=14855 rdcl=2 infs=1 bkbs=6 Mounting disk Finished erase on disk2 |
Verify the partition table again:
~ $ diskutil list /dev/disk0 (internal, physical): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *1.0 TB disk0 1: EFI EFI 209.7 MB disk0s1 2: Apple_CoreStorage Macintosh HD 999.7 GB disk0s2 3: Apple_Boot Recovery HD 650.0 MB disk0s3 /dev/disk1 (internal, virtual): #: TYPE NAME SIZE IDENTIFIER 0: Apple_HFS Macintosh HD +999.3 GB disk1 Logical Volume on disk0s2 03C9C615-4A75-4F55-BFE2-3D1EFAD7519E Unlocked Encrypted /dev/disk2 (external, physical): #: TYPE NAME SIZE IDENTIFIER 0: FDisk_partition_scheme *7.8 GB disk2 1: DOS_FAT_32 NCS1002 7.8 GB disk2s1 |
I had this problem when I upgraded from Yosemite to El Capitan, the built-in FaceTime HD camera did not activate in the FaceTime and other applications.
To fix this issue, run the following:
sudo killall AppleCameraAssistant AND/OR sudo killall VDCAssistant |
If your camera is still not detected, you might need to restart the system.
That’s it!