You don't need the -verbose but it's ok to have it to see what's going on. REFIt usually does all this for you and is easily removable if you don't want it anymore, so in any case, I suggest you give it a try unless you have a specific reason to avoid it. The -legacy basically tells bless that the Operating System that is going to boot doesn't support OpenEFI or EFI and expects a BIOS instead.īear in mind that you might need to later use fdisk to set the active partition if ubuntu fails to boot. With the -setBoot option you're also telling the system to boot from the specified device (must be unmounted as far as I can remember). The 's' was something like: Copy all system files there so this drive can boot. (Kind of what the old format c: /s did in DOS. Bear in mind that blessing does two things, it can select the active boot (which is more or less what you want to do) and it can also make sure that a mount point/folder/device has all the required files for booting. Yes, the bless command has different modes of operation, one is device, which specifies a device (rather than just a folder or a mount point) as the destination for the 'blessing'. Not modified, which can be done with fdisk(8). The active flag of an MBR-partitioned disk is You are interested in this part: -legacy If -setBoot is given, set the firmware to boot a legacy BIOS-based operating While you are at the terminal type: man bless Almost always you will be able to undo what you did, although sometimes at the cost of data loss, naturally. Short Answer: YES, it's reversible, nothing is 'permanent' in a hard-drive partition (other than deleting partitions and information of course).

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