Now that the DreamPlug has a stable power supply (see previous post..) I decided to live dangerously and update the u-boot version and install a modern ‘device tree’ plus kernel..

It has been mentioned many times before that the u-boot update for a DreamPlug is fraught, and can result in a ‘brick’..   There should be a way of recovering from this by use of openocd and the JTAG connection, but I tested this many times, and it simply did not work…    This failure has been documented by several others, and when I see the instruction to ‘keep trying until it works’ I know that something is badly wrong – with the method, or hardware, or both….

There is documentation for DreamPlug u-boot updates, if you look for it..   Most of the info I found was rather ‘old’, and somewhat contradictory!    Remember to take a copy of the old DreamPlug u-boot parameters, as these will get overwritten by the update, and you will need some of the info (including the ethernet mac addresses) to add back..

It is worth mentioning here that you do not need to do this, if you don’t want to!    The latest kernels can be compiled successfully to produce a kernel-with-appended-device-tree image, which will still work with the ‘older’ version of u-boot on the DreamPlug..

However, I finally plucked up the courage, and went from:

U-Boot 2011.06-02334-g8f495d9-dirty (Mar 28 2011 - 05:21:06)
Marvell-DreamPlug

to

U-Boot 2013.07 (Mar 03 2015 - 21:24:17)
Marvell-DreamPlug

There are more recent versions of u-boot, but this version was the only one I found documented for the DreamPlug update that worked, and it does provide support for device-tree (and ext2 boot..) as well..

The kernel source was standard 4.0-rc1 from kernel.org and I cross-compiled the kernel from source in its own directory, including ~/boot and ~/lib sub-directories to receive the kernel image and modules, etc….    As usual, there are other ways of doing this, but this works, for me..

My workflow was:

export ARCH=arm
export CROSS_COMPILE=armv7hl-mandriva-linux-gnueabi-   (insert your own cross-compiler reference here, and don't forget the dash at the end..)
export INSTALL_PATH=../
export INSTALL_MOD_PATH=../

– then run

make multi_v5_defconfig (if necessary..)
make xconfig  (make any necessary changes, for selinux support, etc...)
make
make LOADADDR=000008000 uImage   << Changed March 29, 2015 - Now gives correct amount of total memory after boot >>   **
make modules_install
make firmware_install
cp System.map ../boot
cp arch/arm/boot/dts/kirkwood-dreamplug.dtb ../boot
cp arch/arm/boot/uImage ../boot

Then copy the boot files and lib/modules and lib/firmware contents to the DreamPlug SDCard..

For booting with device tree support, the changed u-boot parameters were:

setenv x_bootcmd_fdt fatload usb 1:1 0xd000000 kirkwood-dreamplug.dtb
setenv x_bootcmd_kernel fatload usb 1:1 0x6400000 uImage
setenv bootcmd '${x_bootcmd_usb}; ${x_bootcmd_kernel}; ${x_bootcmd_fdt}; setenv bootargs ${x_bootargs} ${x_bootargs_root}; bootm 0x6400000 - 0xd000000;'

I was still using fatload, but I may change to boot partition from fat to ext2 in the future and use ext2load..

You may find that the SDCard usb device/address is different – several examples I found showed it as usb 0:1…

After all this, the DreamPlug booted with Kernel 4.0-rc1:

Fedora release 18 (Spherical Cow)
Kernel 4.0.0-rc1 on an armv5tel (ttyS0)
........................
[root@rgdreamplug ~]# uname -a
Linux rgdreamplug 4.0.0-rc1 #1 PREEMPT Mon Mar 2 23:20:37 PST 2015 armv5tel armv5tel armv5tel GNU/Linux

In case you were wondering, the last Fedora version that supports armv5 was F18..

Robert Gadsdon.   March 3, 2015.

** Thanks to Marcus Roeder for this information..