Create a bootable SDHC from a Mac

This page documents the steps to create a bootable SDHC from a Mac running the current OSX and the older MacOS for use in Raspberry Pi.

OSX preparation

To create a FAT16 partition with OSX, use the diskutil program and a USB microSD card reader Put the microSD card in the reader. Connect the reader to a USB port and type ls -1 /Volumes in a terminal. Note the name of the microSD volume; for example, VOL1 in the output below:

 $ ls -1 /Volumes
 Macintosh HD
 Preboot
 VOL1
 

Unmount the reader. Disconnect it and re-run ls -1 /Volumes. Verify the microSD volume name is no longer listed, then re-insert the USB reader.

Find the mount point of your microSD volume. For example, disk3 in the output below:

 $ diskutil list VOL1
 /dev/disk3 (external, physical):
    #:                       TYPE NAME                    SIZE       IDENTIFIER
    0:     FDisk_partition_scheme                        *31.4 GB    disk3
    1:                 DOS_FAT_16 VOL1                    256.0 MB   disk3s1
    2:                      Linux                         30.0 GB    disk3s2
    3:                 Linux_Swap                         1.2 GB     disk3s3
 

(For help with the diskutil command, type diskutil to list all command verbs. For help on a specific verb, add the verb. For example, diskutil partitionDisk)

Destroy all the existing partitions on the microSD card and create two new ones:

1. a 256MB, FAT16, DOS-compatible partition and
2. a free space gap for the rest of the card

 $ diskutil partitionDisk disk3 MBR   "MS-DOS FAT16" VOL1 256MB    "Free Space" VOL2 R
 Started partitioning on disk3
 Unmounting disk
 Creating the partition map
 Waiting for partitions to activate
 Formatting disk3s1 as MS-DOS (FAT16) with name VOL1
 512 bytes per physical sector
 /dev/rdisk3s1: 499472 sectors in 62434 FAT16 clusters (4096 bytes/cluster)
 bps=512 spc=8 res=1 nft=2 rde=512 mid=0xf8 spf=244 spt=32 hds=32 hid=2 drv=0x80 bsec=500000
 Mounting disk
 Finished partitioning on disk3
 /dev/disk3 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *31.4 GB    disk3
   1:                 DOS_FAT_16 VOL1                    256.0 MB   disk3s1

Change your current working directory to the new FAT16 partition

$ cd /Volumes/VOL1/

Continue with the untar instruction in the Unpack files section.

MacOS preparation

Newer versions of MacOS does not allow you to set scheme. Creating MBR using fdisk will result in a disk that MacOS cannot mount. This instructions are out of date for newer versions of MacOS.

• Open disk utility
• Select your SD Card
• Click Erase in the menu
• Set Format to MS-DOS (FAT)
• Set Scheme to Master Boot Record
• Click the Erase button

Unpack files

• Open Terminal
• Check your SD Card is mounted (in this case named "ALPINE")
• Unpack files with sudo tar xf ~/Downloads/alpine-rpi-[...]-armhf.rpi.tar.gz -C /Volumes/ALPINE
• Eject disk, it should now be ready to be used in the Raspberry Pi

After this preparation you should boot the Raspberry Pi with a keyboard and a HDMI screen connected, login as root and run setup-alpine and lbu-commit or follow the Manual Installation.