I’ve tried a few times without success to boot Alpine Linux images on very old Intel Macs. Following the standard instructions, I download the ISO, then image it directly to a USB flash drive. Using this process, the standard x86_64 image boots fine on my more recent MacBook Pro 11,2, but crashes the bootloader on older Macs. (I’ve also confirmed it crashes the bootloader on a 2010 model MacBook.)
Recently, I installed Alpine on an original Raspberry Pi, and I noticed that the instructions were a bit different. Instead of flashing an ISO image, I had to create a blank FAT 32 disk, and copy the files into, rather than copying a disk image. I wondered if this process would make any difference to the boot process on my old iMac. Turns out it does! It booted successfully first try!
- On my Mac, reformat the USB drive as FAT 32, with a Master Boot Record partition table. I’m not sure how necessary it is to configure it with Master Boot Record, but that’s what I did.
- On a Linux PC, download the Alpine x86_64 standard ISO, and mount it. Then copy the files to the USB. NOTE: Copy, from the mounted image, don’t flash the ISO. (This needs to be done on Linux so we can mount the ISO, as Mac won’t be able to mount a Linux ISO.)
- Reboot holding the Option key to enter the bootloader, select the USB disk, and boot!