I have Linux installed on an external (USB 3.0) drive. Since the update to Mojave I have been unable to boot from this disk. I see the missing OS icon, or if there is a version of macOS installed on other drive, the system will boot from that.
I looks as tho there has been a firmware update that has broken non-macOS booting.
Anyone else with Mojave installed able to dual boot Linux?
This is not restricted to Linux. My (formerly working) external usb drive with Windows 10 can no longer boot my machine.
I have no problems using these disks with VirtualBox and can run their repective OS's fine when using VirtualBox's raw disk capability.
The machine is a mid 2017 iMac 5K.
I can confirm that I have the same issue. I very briefly ran the macOS Mojave Beta 2 on my machine and now, even after downgrading back to High Sierra, I am completely unable to boot any Linux USBs. Bootcamp still works, however.
Cannot boot into my windows 10 partition either. Any solutions found yet?
Not tried it with external USB drivess but the only way I can get to my Windows Bootcamp petition on the internal drive is by setting it in System Preferences > Startup Disk. Hotkeys at boot won't work.
YMMV but worth a shot perhaps.
I can confirm the same problem. The system won't boot any OS other than the one on the primary partition.
I found this post to reference the issue: http://netkas.org/?p=1472. Maybe it's a workaround that will work for someone. I assume it's a bug.
Problem is solved after installation of macOS 10.13.6 b5. I noticed an intial boot during the installation that was possibly an update to the firmware. Fingers crossed that it will not be backed out by 10.14 b3.
10.14 B3 has the same bug as is discussed in this thread. Any workarounds?
I guess installing macOS 10.13.6 b5 has a different firmware version than 10.14 b3. Anyway - it worked for me but clearly its not really an option if you don't have a 10.13.x beta disk to do the install.
I’m having same issue.
Maybe this will help but I’m not sure exactly how to follow his instructions: http://netkas.org/?p=1472
Just finished installing their second attempt of 10.14 Beta 3. The issue is still persistent...
This will likely get fixed. I reinstalled bootcamp and everything worked fine includign booting in a different partition than MacOS. However, as soon as I restarted into MacOS, I couldn't reboot into windows.
Small update: Beta 4 (10.14 Beta (18A336e)) Made things worse. The device is now stuck on a blackscreen after choosing Windows and needs to be force shutdown.
Apple seems to somewhat care about it though. At least they requested syslogs on my Bugreport yesterday.
Really hoping this is getting fixed anytime soon though.
It seems USB drivers have something going on with them ...
I boot from external SSD (via USB). Previously, I would hold down option and power on and see boot device options within seconds. Now it takes around 4 minutes (I timed it). Installation onto external SSD via USB via 2016 MBP -- failed... too slow? I managed to get the install and updates to work when using external SSD via USB from an iMac 4K -- but whenever there is an update, it's painful as the reboots all take around 4 minutes to start (each time).
So I bothered updating to 10.14 Beta (18A347e) (DP5) today, without changes. Still stuck on a blackscreen when attempting to boot Windows.
My bugreport from July 13th has been requested logs and then closed without a comment, status says DUPLICATE OF 41368478, which seems to be someone elses bugreport. According to https://forums.developer.apple.com/thread/6885 and the status of my bugreport, that other bugreport seems to be closed too, though. Yet it's not fixed.
