在Mac OS系统中使用镜像安装系统

在Mac OS系统中用户可选择使用dd又或者是图形界面的工具ImagerWriter将系统镜像烧写到SD卡中。

图形界面（常用）

  • 把SD卡插进读卡器中再插入电脑。请务必先将SD卡格式化为FAT32格式。
  • 点击苹果标志，再点击“关于本机”，再点击“更多信息”；如果Mac OS是10.8.x Mountain Lion或者更新的版本，再点击“系统报告”。
  • 点击USB（如果使用内置的读卡器就点击“读卡器”），再在窗口的右上角找到SD卡。
  • Click on USB (or Card Reader if using a built-in SD card reader) then search for your SD card in the upper right section of the window. Click on it, then search for the BSD name in the lower right section; it will look something like ‘diskn’ where n is a number (for example, disk4). Make sure you take a note of this number.
  • Unmount the partition so that you will be allowed to overwrite the disk; to do this, open Disk Utility and unmount it (do not eject it, or you will have to reconnect it). Note that On Mac OS X 10.8.x Mountain Lion, “Verify Disk” (before unmounting) will display the BSD name as “/dev/disk1s1” or similar, allowing you to skip the previous two steps.

  • From the terminal run:

    1.   sudo dd bs=1m if=path_of_your_image.img of=/dev/diskn

    Remember to replace n with the number that you noted before!

Command line

  • If you are comfortable with the command line, you can image a card without any additional software. Run:

    diskutil list

  • Identify the disk (not partition) of your SD card e.g. disk4 (not disk4s1):

    diskutil unmountDisk /dev/<disk# from diskutil>

    e.g. diskutil unmountDisk /dev/disk4

    sudo dd bs=1m if=image.img of=/dev/<disk# from diskutil>

    e.g. sudo dd bs=1m if=2015-02-16-raspbian-wheezy.img of=/dev/disk4

    This may result in an dd: invalid number '1m' error if you have GNU coreutils installed. In that case you need to use 1M:

    sudo dd bs=1M if=image.img of=/dev/<disk# from diskutil>

    This will take a few minutes.

Alternative method

Note: Some users have reported issues with using Mac OS X to create SD cards.

These commands and actions need to be performed from an account that has administrator privileges.

  • From the terminal run df -h.
  • Connect the SD card reader with the SD card inside.
  • Run df -h again and look for the new device that wasn’t listed last time. Record the device name of the filesystem’s partition, for example /dev/disk3s1.

  • Unmount the partition so that you will be allowed to overwrite the disk:

    1.   sudo diskutil unmount /dev/disk3s1

    (or open Disk Utility and unmount the partition of the SD card (do not eject it, or you will have to reconnect it)

  • Using the device name of the partition, work out the raw device name for the entire disk by omitting the final “s1” and replacing “disk” with “rdisk”. This is very important as you will lose all data on the hard drive if you provide the wrong device name. Make sure the device name is the name of the whole SD card as described above, not just a partition of it (for example, rdisk3, not rdisk3s1). Similarly, you might have another SD drive name/number like rdisk2 or rdisk4; you can check again by using the df -h command both before and after you insert your SD card reader into your Mac. For example, /dev/disk3s1 becomes /dev/rdisk3.

  • In the terminal, write the image to the card with this command, using the raw disk device name from above. Read the above step carefully to be sure you use the correct rdisk number here:

    1.   sudo dd bs=1m if=2015-02-16-raspbian-wheezy.img of=/dev/rdisk3

    If the above command reports an error (dd: bs: illegal numeric value), please change bs=1m to bs=1M.

    If the above command reports an error dd: /dev/rdisk3: Permission denied then that is because the partition table of the SD card is being protected against being overwritten by MacOS. Erase the SD card’s partition table using this command:

    1.   sudo diskutil partitionDisk /dev/disk3 1 MBR "Free Space" "%noformat%" 100%

    That command will also set the permissions on the device to allow writing. Now try the dd command again.

    Note that dd will not feedback any information until there is an error or it is finished; information will be shown and the disk will re-mount when complete. However if you wish to view the progress you can use ‘ctrl-T’; this generates SIGINFO, the status argument of your tty, and will display information on the process.

  • After the dd command finishes, eject the card:

    1.   sudo diskutil eject /dev/rdisk3

    (or: open Disk Utility and eject the SD card)

This article uses content from the eLinux wiki page RPi_Easy_SD_Card_Setup, which is shared under the Creative Commons Attribution-ShareAlike 3.0 Unported license