Goal: To install Macintosh System 7.5.3 from scratch using only 1 SCSI2SD and a Linux PC with an SD card reader.
- The Mac cannot be booted using a floppy disk, or any other disk
Step 1: Create the HFS filesystem image
Install your Mac OS (System 6 or 7) using an emulator. This is by far the easiest way to get started! Be sure to create the emulated disk a little smaller than the SD card you'll be using. eg. for a 2GB SD card create a 1.9GB disk image.
The following emulators have been tested to produce usable HFS disk images:
Step 2: Prepend an Apple Partition Map to the image
We'll use hfdisk to create the partition table. We want to end up with the following partition layout:
|type||name||Starting Sector||# of sectors||Description|
|Apple_partition_map||Part Map||1||63||Partition table|
|Apple_Driver||Driver_Partition||64||32||SCSIManager driver, normally provided by Apple Drive Setup|
|Apple_HFS||Mac Volume||96||...||Installed OS from emulator.|
Determine how many sectors your emulated disk image.
Sectors = (size of emulated HFS disk image) / 512.
The partition map and driver partition require 96 sectors. Create an empty file that is 96 sectors larger than the emulated disk image. In the following example, the emulated disk image is 1887436800 bytes, which is 3686400 sectors.
$ dd if=/dev/zero of=disk.img bs=512 count=3686496
Use hfdisk to create the partition layout:
$ ./hfdisk disk.img
Command (? for help): i Device block size : new size of 'device' is 3686496 blocks Command (? for help): C First block : Length (in blocks, kB (k), MB (M) or GB (G)) : 32 Name of partition: Driver_Partition Type of partition (L for known types): Apple_Driver Command (? for help): C First block : Length (in blocks, kB (k), MB (M) or GB (G)) : Name of partition: Mac_Volume Type of partition (L for known types): Apple_HFS Command (? for help): p disk.img # type name length base ( size ) system disk.img1 Apple_partition_map Apple 63 @ 1 ( 31.5k) Partition map disk.img2 Apple_Driver Apple_Driver 32 @ 64 ( 16.0k) Driver disk.img3 Apple_HFS Apple_HFS 3686400 @ 96 ( 1.8G) HFS Block size=512, Number of Blocks=3686496 DeviceType=0x0, DeviceId=0x0 Drivers- 1: @ 64 for 32, type=0x1 Command (? for help): w IMPORTANT: You are about to write a changed partition map to disk. For any partition you changed the start or size of, writing out the map causes all data on that partition to be LOST FOREVER. Make sure you have a backup of any data on such partitions you want to keep before answering 'yes' to the question below! Write partition map? [N/y]: y The partition map has been saved successfully! Partition map written to disk. If any partitions on this disk were still in use by the system (see messages above), you will need to reboot in order to utilize the new partition map. Command (? for help): q
Step 3: Copy a SCSI driver partition
I've found that lido driver partitions are the most portable.
$ dd if=lido.img of=disk.img seek=64 bs=512
Step 4: Copy the emulator HFS filesystem
Copy the image file created by the emulator into the disk image.
$ dd if=emulator_disk.img of=disk.img seek=96 bs=512
Step 5: Boot your Mac!
Write the disk image to an sd card, then put the SD card in the SCSI2SD and boot the Mac:
$ sudo dd if=disk.img of=/dev/sdX