Revive An Old Mac

Background

This project started with a old MAC I found on the street, which was thrown away by someone. It is a 2006 model with 32-bit EFI and 64-bit CPU. The problem is that the latest macOS version it can run is 10.7.5, which is too old to run most of the software I need. So I decided to install a Linux OS on it. However, the 32-bit EFI makes it impossible to install a 64-bit Linux OS. After some research, I found a way to install a 64-bit Linux OS on a 32-bit EFI Mac. The following is the procedure.

Prepare an USB Stick with 32-bit EFI and 64-bit Linux.

1. Insert a usb stick and find its name on Mac. The following commands are used based on the stick name disk2:

   diskutil list
   

2. Write zero to the disk and quit the process after abut 10 seconds by Ctrl+c. Before running the following command, you may need to run diskutil unmountDisk /dev/disk2 to avoid Resource busy error.

   sudo dd if=/dev/zero of=/dev/disk2
   

3. Create an EFI partition on the stick using diskutil, format is set to MS-DOS(FAT) and Scheme is set to GUID Partition Map. Then check the EFI partition identifier via diskutil list. Suppose its identifier is disk2s1. Note that the EFI partitin is not mounted by macOS by default so you have to manually mount it by yourself:

   mkdir /tmp/sdb1
   sudo mount -o rw -t msdos /dev/disk2s1 /tmp/sdb1
   

4. Create some folders in the EFI partition:

   sudo mkdir -p /tmp/sdb1/boot/grub/
   sudo mkdir -p /tmp/sdb1/efi/boot/
   

5. Create grub.cfg file in /tmp/sdb1/boot/grub/ and write the following lines:

   search --file --set=root /boot/grub/loopback.cfg
   configfile /boot/grub/loopback.cfg
   

6. Download a bootia32.efi:

   wget https://github.com/jfwells/linux-asus-t100ta/raw/master/boot/bootia32.efi
   

7. Copy the bootia32.efi to /tmp/sdb1/efi/boot/ and then unmount the drive:

   sudo cp /path/to/bootia32.efi /tmp/sdb1/efi/boot/
   

8. Put the ISO image on the second partition (suppose its identifier is disk2s2). You may need to run diskutil unmountDisk /dev/disk2 to avoid Resource busy error:

   sudo dd if=/path/to/lubuntu.iso of=/dev/disk2s2 bs=1M.
   

Install the OS.

1. Insert the USB stick to the old Mac.
2. Power on the machine and hold the Alt key until two drivers show on the screen.
3. Choose the EFI and press Enter.
4. Wait for a couple of seconds and some texts like “Try Lubuntu…” show up, then press e to edit the boot options. Change quiet splash to nomodest splash . This is the one I use, you may change it according to your needs. For more options: boot options.
5. Press f10 to save the changes and start installing.

References:

1. ISO images can be found here: mattgadient.com.
2. Adapt the method from Live CD on an USB Stick and adjust to the macOS environment.