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question about the Debian preloaded SD card

ykwong

I recently bought a model B RaspPi and a Debian preloaded SD Card (4G) from Element14. 

Booting up is ok, though I have not really tried to use it long enough to see if it has any voltage drop or heat problem. 

 

My question is :

I do not want to damage (or alter the original state of) my one-and-only-one o/s preloaded SD card.  So I bought a blank 4G SD card and try to make a duplicate and from there I intend to use the duplicate only.  By the way, having a duplicate card is also handy when I decide to buy one more Rasp-Pi.

 

I found that if I use my duplicated SD Card, the bootup is not successful, it will not stop at the Linux prompt that allows me to start the X Window.  It stops midway in the bootup process and I have no choice but to switch the power off.

 

Obviously, I think my method of the card duplication was wrong. Here is how I duplicated the SD card.

I inserted the original in my Mac (which has a built-in SD card slot),

I copied all the files (these are not images file already as the card is bootable) from the original SD into a folder on my Mac harddisk.

Then I inserted the blank 4G SD card in my Mac, and copy those files back from the harddisk to the SD card.

 

I probably did it the wrong way or this method will never duplicate the card successfully.

 

What would be the correct way to do what I want to achieve?

 

I am grateful to any advice, information, comments....

Parents

  • The Pi sd card has 2 partitions. One smaller fat32 partition (50 - 70MB) is used for the boot files and the kernel.

    The other ext4 partition is used for the linux root filesystem.

    I have no Mac experience, but obviously, only copiing the files won't do the trick.

    In linux, you need to dd the sd card contents to a file. After that, you can dd them back to the other card. 

     

    Be very carefull with the dd command, as it can also overwrite your harddisk or parts of it when it's not properly used.

    (It's nickname is disc destroyer)

     

    dd will also transfer the sd card sector 0, so the backup sd card will have the same partition layout as the original one.

  • in reply to Former Member

    Hi LC,

     

    Thanks for your advice.  After reading your post, I guess I should try the following (at least in principle)

     

    (by the way, switching to command mode from GUI in a Mac is almost identical to be running any Linux computer)

     

    (1) make an empty folder in my Mac and mount it as a drive

    (2) insert the original SD into the SD slot and use the dd command to copy the files from the original to the newly mounted drive (which is actually a folder on the Mac HD).

    (3) Place the blank SD inside the SD slot and use the dd command again, but this time files are copied from the mounted drive back to the SD card. 

     

    Now the only problem is I need to learn all the syntax of the dd command. 

     

    Are these procedures correct?  Or did I miss any crucial step?

  • in reply to ykwong

    dd works sector based. To my knowledge, you can even dd directly to a file.

    It might be worth to have a look at the elinux rPi section. They describe how to transfer an image file to the sd card. (Probably for Mac as well.)

    Just make sure you transfer it to SDx (your sd card) and not to SDx1 (the first partition of your sd card) This is a commonly made mistake.

     

    And always make sure it's your SD card and not your MAC harddisk !!!!!!!

     

    A 4Gig sd card will create a 4Gig image file. You might compress it after use.

Reply
  • in reply to ykwong

    dd works sector based. To my knowledge, you can even dd directly to a file.

    It might be worth to have a look at the elinux rPi section. They describe how to transfer an image file to the sd card. (Probably for Mac as well.)

    Just make sure you transfer it to SDx (your sd card) and not to SDx1 (the first partition of your sd card) This is a commonly made mistake.

     

    And always make sure it's your SD card and not your MAC harddisk !!!!!!!

     

    A 4Gig sd card will create a 4Gig image file. You might compress it after use.

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