I am booting a retrogaming system (Recalbox, linux-based) on my Macbook Pro 2009 (Intel, El Capitan) from an SD card (FAT format). The SD card is currently displayed as "EFI boot" upon boot drive selection (*al*t key upon startup), as it currently displays "EFI boot". I would like to change that label ("RECALBOX", for example). I have been through many ressources online and tried the

command as advised here: https://apple.stackexchange.com/questions/388246/efi-partition-change-name-and-logo My version:

--folder /Volumes/RECALBOX/EFI/boot --label "RECALBOX"

It does create the expected hidden files in the folder .disk_label
.disk_label_2x but the default "EFI boot" label doesn't change in the boot selection on startup. Any ideas if I'm missing something? Thanks for your help!

I asked this on the Ubuntu exchange where I personally think it belongs, but they directed me here so please don't close this and tell me to ask there. I'm booting from the Mac OS X Lion installation disk that comes with the laptop and then opening a terminal from inside that. So after trying out different variations, here are the results: bless --device /dev/disk0s1 --setBoot doesn't appear to do anything. Still long timeout on white screen. System still booting afterwards. bless --device /dev/disk0s2 --setBoot same as above. bless --device /dev/disk0s1 --setBoot --legacy still long timeout on white screen. After that system goes to black screen and won't boot into Ubuntu. There are only /dev/disk0s1 and /dev/disk0s2 listed in fdisk for /dev/disk0. I'm assuming /dev/disk0s1 is /boot/efi but I have no idea. I have performed a full-disk install of Ubuntu 22.04 on an old MacBook Pro (MBP 5.2 from 2009, Core 2 Duo) machine completely wiping OSX in the process. I'm now facing the known issue of the 30-second white screen delay on boot. I already figured out I have to use the bless utility to set Ubuntu as the boot partition. My question is what command-line arguments do I have to pass exactly? All examples on the internet make use of the --legacy option and talk about BIOS mode but from what I could figure out my Ubuntu installation is using EFI (the /sys/firmware/efi directory exists ). I assume then that I shouldn't use the --legacy option when blessing the partition. Here's the output of df -h when run in Ubuntu: t30@macbook:~$ df -h tmpfs 770M 1,7M 768M 1% /run /dev/sda2 457G 12G 423G 3% / tmpfs 3,8G 0 3,8G 0% /dev/shm tmpfs 5,0M 4,0K 5,0M 1% /run/lock /dev/sda1 511M 6,1M 505M 2% /boot/efi tmpfs 770M 52K 770M 1% /run/user/1000 I think I should invoke bless like this (replacing /dev/sda1 with whatever it's mounted as under bless). bless --device /dev/sda1 --setBoot Is there a guide or can someone confirm which partition do I have to bless?

I have one of those MacBook Pro's (2015) with the hardware fault which causes frequent spontaneous shutdowns. The problem can be solved by renaming or deleting AppleThunderboltNHI.kext which I have done after every MacOS Catalina update for the past couple of years, basically everything except step 7 & 8 below. In Big Sur, the change doesn't "stick," the AppleThunderboltNHI.kext file is restored automatically after restarting in normal mode, so I have followed the procedure which works according to many on the discussion referenced below. Everything goes okay unless I do step 8, at which point the MacOS will not boot, I get a message like "...was restarted because of a problem..." The only thing that seems to fix that, is to reinstall Big Sur from recovery mode, which does work. But then the AppleThunderboltNHI.kext file is restored. I don't know is causing this procedure to fail. So I'm hoping someone might be able to help me solve it. Note: The following instructions are not mine, and I am not recommending them as a solution. https://developer.apple.com/forums/thread/666567?answerId=646500022#646500022 > Posted by sf98723 > > Follow this procedure : > 1. Reboot in rescue mode (reboot while "Cmd + R") > 2. csrutil disable > 3. csrutil authenticated-root disable > 4. reboot in rescue mode > > 5. mount -uw /Volumes/[MacOS ] > > 6. delete (or rename, or move elsewhere) the AppleThunderboltNHI.kext directory (I've moved all thunderbolt kext directories since I have no > needs about this interface, but I think it works only by disabling > AppleThunderboltNHI) > > 7. REBUILD the extensions cache ! (new has-to-do in Big Sur...) : kmutil install -u --force --volume-root /Volumes/[MacOS stuff here>] > > 8. DON'T FORGET to create another system snapshot to take these modifications under account at next reboot : bless --folder > /Volumes/[MacOS ]/System/Library/CoreServices > --bootefi --create-snapshot > > 9. csrutil enable (mays be you have to reboot in rescue mode.. not tested) > > 10. Finally, reboot in normal mode

I am trying to install rEFInd on my MacBook Pro 2018 laptop with the new T2 chip that adds extra boot security. I have both used APFS and MacOS Extended (Journaled). I have also disabled secure boot and csrutil. When I install rEFInd using sudo ./install.sh --alldrivers --ownhfs /dev/disk0s3 (where disk0s3 is my MacOS Extended (Journaled)), I then get an error when selecting the rEFInd disk in the Startup Disk, I end up getting an error saying that there was a bless error. How would I install rEFInd on my MacBook Pro 2018 laptop? **Edit**: If it helps, I am on macOS High Sierra and will soon be updating to macOS Mojave in the next few weeks. This is also the format of my disk: /dev/disk0 (internal): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme 500.3 GB disk0 1: EFI EFI 314.6 MB disk0s1 2: Apple_APFS Container disk1 499.7 GB disk0s2 3: Microsoft Basic Data BOOTMGR 307.2 MB disk0s3 /dev/disk1 (synthesized): #: TYPE NAME SIZE IDENTIFIER 0: APFS Container Scheme - +499.7 GB disk1 Physical Store disk0s2 1: APFS Volume Macintosh HD 199.5 GB disk1s1 2: APFS Volume Preboot 44.6 MB disk1s2 3: APFS Volume Recovery 1.0 GB disk1s3 4: APFS Volume VM 1.1 GB disk1s4

I bought a used Mac mini from a reliable source. He factory reset it, so we set about upgrading to the highest we can, High Sierra. I created a bootable USB on my iMac using the High Sierra installer. Inserted it, booted from it and installed the OS. All looked good, and we got into the OS on first load. Upon restarting, it says “MacOS could not be installed on your computer. An error occurred while loading the installer resources” "Quit the installer to restart your computer and start again". Weird, because the installation has finished and the USB drive is no longer in there. It also mentioned something about bless but I can't remember what. This machine has an SSD, I THINK when it arrived there were two partitions but only one now. I have no idea about SSDs, never used one before. Does it need a separate partition for booting or something? Totally lost, would be very grateful for some help.

There is a Windows 10 EFI/GPT installation on a separate drive in my MacPro next to my disk with the OSX installation. The Apple Startup Manager shows the Win10 disk labeled as "EFI Boot". I can boot to Win10 there. I cannot set the default startup disk in system preferences. If I choose the Win10 HDD I will get "No Bootable Device -- Insert boot disk and press any key" error upon next boot. As soon as I bless the OSX disk again through system preferences OSX will boot again as standard. How can I "bless" the Win10 disk as the standard disk to boot upon startup? There is no EFI partition present on the Win10 disk. Thanks. diskutil list output: /dev/disk6 (external, physical): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *250.0 GB disk6 1: Microsoft Reserved 16.8 MB disk6s1 2: Microsoft Basic Data BOOTCAMP 249.5 GB disk6s2 3: Windows Recovery 471.9 MB disk6s3 /dev/disk7 (external, physical): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *256.0 GB disk7 1: EFI EFI 209.7 MB disk7s1 2: Apple_HFS Macintosh HD 255.1 GB disk7s2 3: Apple_Boot Recovery HD 650.0 MB disk7s3 **UPDATE:** Windows installer seems to have used the EFI partition on disk7 to copy the boot files to. I managed to "repair" the startmanager with this guide here . Windows now boots on every startup of the MacPro. I can also access the Apple Startup Manager and choose my Macintosh HD or the Recovery Partition. As soon as I mess around with choosing the startup disk in osx system preferences it will break again with the "no bootable device error". OSX or the Startup Manager does not seem to be able to find the Windows OS on the other disk6 without EFI Partition. Interesting also is that even when I disconnect the windows disk7 I will still see EFI Boot in Apple Startup Manager. Choosing it will get a Windows Error screen not being able to boot of course. As soon as I have more time I will continue to experiment further... Maybe somebody with a better understanding of the Apple EFI Startup Manager can give a hint in advance how to make it possible to switch startup disk from OS side in a "normal" way. Next step to try: Add EFI partition to Windows disk6 put the Win startup files there and link to the installation on the same disk.

The computer is an early 2015 13" MacBook Pro. Two weeks ago we sent my spouses 15" in for battery recall, and bought an OWC Aura Pro to replace my internal 1GB SSD (we SuperDuper'd her 15" MacBook's hard drive onto the Aura). So we took my internal SSD out and put it in the External OWC case. I was able to start up my computer once or twice from the external without a problem. Yesterday, we got the computer back and put the Aura into her 15" MacBook (no problems there), but when I put my SSD back in my 13", it would boot only so far and then restart. I put the SSD back into the external case and started the 13" fine off of my spouses original SSD (from her 15"). In Startup Disk, when I tried to select my SSD and click restart, I get the bless tool error. The question is, what's my next move? Can this be repaired? (Disk Utility didn't fix it). The questions I've found on Google tend towards the new disk territory, but this is an unmodified Apple SSD that had been fine until I took it out of my computer. Worst case, I have a SuperDuper backup on a platter disk. I figure I can reformat the SSD and SuperDuper the data back onto it from the external, but I'm not sure if that will perpetuate the issue.

As part of our standard deployment, we tend to deploy multiple OSs on Macs, from 10.7 to 10.11. However, with the new SIP (System Integrity Protection), the -bless command no longer works properly. I need the Macs to boot to each OS during the initial configuration to properly name the OS for Active Directory binding and then do the actual binding. I've tried to use the "csrutil disable" command recommended in some other places, but that requires booting into the Recovery OS and that change is stored in the NVRAM, so it's local to whatever machine I'm using. Meaning that it won't be part of the 10.11 image deployed. In the end, I need to be able to script multiple -bless commands, telling the Mac to boot to different OSs on separate partitions on the internal hard drive. It's critical to the image process. Does anyone have any idea on how to do such a thing?

I'm getting an SSD for my wife's MBP 2010. I was planning to install the old HDD and the new SSD into my MacPro and just use disk utility to copy all the info from her old disk to the new one. It would be easy enough and once the new disk is installed she can pick right up where she left off. But I had an idea to reduce her downtime while the disks were copying. If I install the SSD into my MacPro first. then copy all the files over the network from her MBP onto the SSD. All I would need to do is bless the new SSD and I should be able to just swap the two drives and it should be perfectly bootable with all files and settings intact right? the MBP only needs to be down for the 15mins it takes me to change the drives. I'm just a little bit confused about how Bless works though. It just lets the computers firmware know where to find the boot-loader right? but is that info saved in the firmware? or is it apart of whatever filesystem the Blessed files exist on? I guess what I'm asking is, if I bless the SSD while it's in my MacPro, will it mess up the MacPro's boot settings? and Not make the SSD bootable? Or will it work like I hope it does and just make the SSD bootable so that it can go into the MBP and just work? Or do I need to add extra options for that? PS: yes I realize that this all just creates a bunch of extra work for me to save an hour (at most) of downtime on the laptop. But I had the idea and now I want to know. Thanks!

Currently, I am able to mount and edit the EFI partition without any special privileges. Is that correct? I understand that the bootflags for SIP protected regions are stored in nvram which is inaccessible through bless, but it seems strange that I can manipulate the binary, and the changes will persist through a restart. Is something wrong here? If not, why is it the case?

On my late 2012 Mac Mini, I have installed both Mac OS X Mavericks (with FileVault) and Windows 8.1 (natively, not via Bootcamp): /dev/disk0 #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *1.0 TB disk0 1: EFI EFI 268.4 MB disk0s1 2: Apple_CoreStorage 859.0 GB disk0s2 3: Apple_Boot Recovery HD 650.0 MB disk0s3 4: Microsoft Reserved 134.2 MB disk0s4 5: Microsoft Basic Data Windows 140.2 GB disk0s5 That's working fine, and I can boot both Mac OS and Windows. However, I'd like to be able to boot my Mac into Windows from the command line - without permanently changing boot settings. To my understanding, this should do it: sudo bless -mount "/Volumes/Windows" -setBoot --nextonly The command produces no output. With --verbose, it tells me this: EFI found at IODeviceTree:/efi Mount point for /Volumes/Windows is /Volumes/Windows Mount point is '/Volumes/Windows' No BootX creation requested No boot.efi creation requested found ioreg "FirmwareFeaturesMask"; featureMaskValue=0xE003FF37 found ioreg "FirmwareFeatures"; featureFlagsValue=0xE001F537 isPreBootEnvironmentUEFIWindowsBootCapable=1 given BSD is not a DVD disc medium isDVDWithElToritoWithUEFIBootableOS=0 Checking if disk is complex (if it is associated with booter partitions) GPT detected Booter partition required at index 6 System partition found Preferred system partition found: disk0s1 Returning booter information dictionary: {type = mutable dict, count = 3, entries => 0 : {contents = "System Partitions"} = ( disk0s1 ) 1 : {contents = "Data Partitions"} = ( disk0s5 ) 2 : {contents = "Auxiliary Partitions"} = ( ) } Path to mountpoint given: /Volumes/Windows IOMedia disk0s5 has UUID D4FC6318-275B-427D-B039-3AB033DE8ACC Setting EFI NVRAM: efi-boot-next='IOMatchIOProviderClassIOMediaIOPropertyMatchUUIDD4FC6318-275B-427D-B039-3AB033DE8ACCBLLastBSDNamedisk0s5' Setting EFI NVRAM: IONVRAM-DELETE-PROPERTY='efi-boot-file' Setting EFI NVRAM: IONVRAM-DELETE-PROPERTY='efi-boot-mkext' Setting EFI NVRAM: IONVRAM-DELETE-PROPERTY='efi-boot-kernelcache' NVRAM variable "boot-args" not set. That looks good to me - but the command has no effect, after rebooting, I'm back in Mac OS X. What am I doing wrong?

Ok strange one this and really can't figure it out. Took out a dead 250gb apple (fujitsu) drive from 13" 2.53 intel core 2 duo (mid 2009) model. I cloned a copy of 10.6.8 using superduper to the new samsung 1TB 2.5" drive, test booted up via a sata/usb cable via the macbook pro and all working fine. My problem comes once the new drive is installed into the macbook pro it can't seem to boot from the 1TB drive at all. Disk utilities also does seems to be able to scan it correctly either and seems sluggish and it won't even let me format the drive via disk utilties either. First I thought it was the new 1TB drive, but I've just had a 2nd drive delivered and cloned the same copy of 10.6.8 on to the 2nd new drive. All boots fine via sata/usb cable then once installed in macbook pro it won't boot from the new drive. Tried holding alt to give boot options, it see drive and tries to boot but stops at apple logo. Booted in via a clone of 10.9 on any external drive all boots fine and i can see the new internal 1TB drive. When I try to change the startup disk to the internal 1TB i get the drive is unable to be blessed. I know the drive is formated correctly and I know it boots via the sata/usb cable via the macbook pro. My only think is there is something wrong with the sata cable to logic board on the macbook pro now? As any drive will boot with a system via usb, but once i install either of the x2 different new 1TB drives inside the macbook pro it won't boot and can't seem to format the drives either. Any help would be greatful, not sure what i else i can do now?

Is there a guide on how to bless a partition for booting, one that doesn't have the default /System/Library/CoreServices/boot.efi structure? For example, I installed GRUB on the default EFI System Partition (/dev/disk0s1in OS X, /dev/sda1 in Linux) and I have the file /EFI/arch_grub/grubx64.efi that I want to use instead of /System/Library/CoreServices/boot.efi. Normally, following the standard structure, I would copy grubx64.efi to /System/Library/CoreServices/boot.efi and also touch /mach_kernel in the partition I want to make bootable, then I'd run the following to bless the partition: # bless --folder= --file=/System/Library/CoreServices/boot.efi --setBoot # bless --mount= --file=/System/Library/CoreServices/boot.efi --setBoot To install GRUB, I followed the instructions in the Arch Linux Beginners' guide, which leaves me with (something like) /EFI/arch_grub/grubx64.efi file, where word arch_grub is arbitrarily chosen. Then running the following commands succeeds with no errors: # bless --folder= --file=/EFI/arch_grub/grubx64.efi --setBoot # bless --mount= --file=/EFI/arch_grub/grubx64.efi --setBoot But the partition doesn't show up in the Apple boot menu, and sudo bless --verbose --info shows: ┌─[02:31:54/trusktrs-MacBook-Pro/trusktr//tmp] └─╼ sudo bless --verbose --info /tmp/boot/ Mount point for /tmp/boot/ is /private/tmp/boot GPT detected Booter partition required at index 2 System partition found Preferred system partition found: disk0s1 Returning booter information dictionary: {type = mutable dict, count = 3, entries => 0 : {contents = "System Partitions"} = ( disk0s1 ) 1 : {contents = "Data Partitions"} = ( disk0s1 ) 2 : {contents = "Auxiliary Partitions"} = ( ) } I made sure to touch /mach_kernel then unblessed and re-blessed the partition using the same commands but no luck. I bet I'm missing something(s) simple and that it's not difficult to do what I want, but I'm not exactly sure what I need to do. Any tips/ideas/suggestions?

I am using the bless command to reboot my Mac mini into VMware ESX. sudo bless --device /dev/disk3s1 --setboot --nextonly && sudo reboot Booting ESX works but after the next reboot the Mac reboots into ESX again, despite the "--nextonly" parameter. The same command (with a different device) works for rebooting into Windows on the Boot Camp partition once, i.e. after booting into Windows the Mac mini reboots into OS X again. But it doesn't work with booting into ESX. Any ideas? Update: With the --legacy switch the nvram variable is changed to boot from USB and uses the BIOS emulator, which promptly boots from the Windows partition. So that doesn't work.