Martin Michlmayr
SheevaPlug in my hand


This page describes common problems that users of Debian on plug computers have run into. If you have any problems with your plug computer, either while trying to install Debian or when running Debian, please look through this page carefully to see whether you can find a solution. If your problem is not covered here, feel free to contact the debian-arm list for help. Always include the full boot log as well as the output of printenv from U-Boot.


Cannot connect to serial console

If you cannot connect to the serial console of your plug computer, make sure that your device is working correctly. It has been reported that the power supply for SheevaPlug devices can stop working after continued use, so this might be the reason why you cannot connect to the serial console.

If your device is working correctly but you get a "permission denied" error when connecting to the serial console, make sure that your user is in the dialout group. This is the group associated with the /dev/ttyUSBx device nodes.

No output after "Uncompressing Linux..."

You get no output after seeing this line:

Uncompressing Linux... done, booting the kernel.

If you've just upgraded from Debian 6.0 (squeeze) to Debian 7 (wheezy), your version of u-boot is too old. You need 2011.12-3 (or higher). Please upgrade u-boot and everything will work again. There's no need to re-install Debian!

Error "Bad Magic Number" when loading image

Some users report that they get the following error when booting:

## Booting image at 00400000 ...
Bad Magic Number

In most cases, the problem is not with the image itself but with loading the image. Take a look at the whole boot log and you'll probably find an earlier error, typically related to loading the image (maybe you specified a wrong location for the boot image; maybe the TFTP server didn't respond; maybe U-Boot failed to load the image from your USB stick). Look for the first problem in your boot log and you'll probably be able to figure out the solution.

Error "** Unable to read "/uImage" from usb 0:1 **" when booting

If you receive the error message Unable to read "/uImage" from usb 0:1 when booting the first time, it's likely that 0:1 is not the correct boot partition. 0:1 refers to device 0 and partition 1 but it's possible that your boot partition is on a different device or partition.

In order to find out the correct device, you can use usb dev (for USB) or ide dev (for SATA) to see all devices. (Unfortunately, it's not possible to list devices and partitions for MMC/SD cards with the current version of u-boot.) In the following example, there is a single USB device (device 0):

Marvell>> usb dev

USB device 0: Vendor: A-JET    Prod.: USB 2.0 0812     Rev: 1.00
            Type: Removable Hard Disk
            Capacity: 1970.0 MB = 1.9 GB (4034560 x 512)

You can now display all partitions for this device with the usb part command (or ide part for SATA devices):

Marvell>> usb part 0

Partition Map for USB device 0  --   Partition Type: DOS

Partition     Start Sector     Num Sectors     Type
    1                 2048          317440      83
    2               319488         3211264      83
    3              3532798          499714       5 Extd
    5              3532800          499712      82

There are two partitions with the ext2/ext3 filesystem (type 83) and one extended partition for swap (type 82). The first partition (partition 1) is the boot partition.

In the example, the device is device 0 and the boot partition is partition 1. Therefore, the correct path is 0:1. However, in your case it might be something else.

Output "T T T T" when loading via TFTP

Some users report that they get the following output when loading an image via TFTP:


This means that the TFTP server doesn't respond. Ensure that you specified the right IP address of the TFTP server and location of the image.

Also note that resetting the U-Boot environment may cause the plug computer to try to load an image via TFTP. If you unexpectedly see the T T T messages, check your U-Boot configuration with printenv to ensure it's loading the image from the right location.

Boot fails with LVM on USB drive

If you have installed Debian on a USB drive and put the root device on a LVM volume it's possible that the system won't boot because Debian tries to access the LVM volume before the USB drive is recognized. To avoid this problem, pass a rootdelay parameter to the kernel. For example, issue the following commands in U-Boot to give the USB drive 10 seconds to appear:

bootargs_console console=ttyS0,115200 rootdelay=10

Loading image from a USB stick with FAT fails

U-Boot may have problems loading an image from a FAT32 filesystem whereas FAT works. I believe you can make a FAT filesystem under Linux with the following command:

mkfs.vfat -F 16

Debian installer

Formatting the disk is stuck at 33%

Formatting the disk may take a long time, especially if you have a large disk. Unfortunately, the progress bar is not updated while the disk is being formatted so you may think that it is stuck (at 33%). If this happens, just be patient. The installer is in fact formatting your disk.

eSATA disk not found on eSATA SheevaPlug

If your eSATA disk is not recognized on your eSATA SheevaPlug when booting Debian or the Debian installer, it's probably due to a missing u-boot configuration. On eSATA SheevaPlug devices (but not other devices), you have to configure u-boot like this:

setenv machid a76

These commands will put in the correct settings and then restart the device so the changes will take effect.

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