thanks OGnerd can you tell me the command usThe bless command sets volume bootability and startup disk options. In some circumstances these may be altered by volume manipulations and require resetting. It can make the difference in a volume being bootable or not.
With the introduction of El Capitan, Apple introduced an enhanced system security mechanism dubbed System Integrity Protection which effectively locked down certain system directories from unauthorized changes; not even the root account is allowed to make changes to the contents of those directories. Disabling SIP (which officially cannot be accomplished from a running system, ie. it must be done from the Recovery platform) affords the system security level of Yosemite. SIP is the reason that Pike R. Alpha had to develop an entirely new boot.efi for El Capitan, and why the PikeYosFix script that shielded users from system software update changes that reverted back to the original boot.efi, no longer works.
what command is that?The bless command sets volume bootability and startup disk options. In some circumstances these may be altered by volume manipulations and require resetting. It can make the difference in a volume being bootable or not.
With the introduction of El Capitan, Apple introduced an enhanced system security mechanism dubbed System Integrity Protection which effectively locked down certain system directories from unauthorized changes; not even the root account is allowed to make changes to the contents of those directories. Disabling SIP (which officially cannot be accomplished from a running system, ie. it must be done from the Recovery platform) affords the system security level of Yosemite. SIP is the reason that Pike R. Alpha had to develop an entirely new boot.efi for El Capitan, and why the PikeYosFix script that shielded users from system software update changes that reverted back to the original boot.efi, no longer works.