Nine years ago I bought Sharp Zaurus SL-5500 as my first Linux PDA. And due to this I am where I am.

I could say that it started two years earlier when I saw PalmOS devices at local geek meetings. But it took me over year before Palm m105… Then was Sony Clie SJ30 — gorgeous device. High resolution, memory card, 16bit colour. Too bad that applications did not make use of it.

So I went for Linux. There were two options: Zaurus or iPaq. Went for former one as it had keyboard. It was good choice.

Quickly started development of packages and joined OpenEmbedded team. Then became one of OpenZaurus developers. After year or something took over release maintenance and released few last versions. 3.5.4(.1) were the best tested releases of OZ ever — I had over hundred testers for each RC image and they provided installation reports, bug reports and fixes. And it had unified installer for whole range of devices (took me several months to get it polished and few guys added own tweaks). When Ångström distribution started I was the one who officially ended OpenZaurus development.

And all that was in free time. But in mean time I created my consulting company. CELF was my first customer ;)

One nice evening I got question on irc and due to that I left dark side of IT and went from PHP programming to embedded Linux full-time. OpenedHand had interesting projects and clients with many devices. Imagine operating system + kernel + Python + GStreamer in 16 megabytes of flash… And I managed to get it done. While working for them I used proper developer boards (not only customer devices) and there were funny moments…

When we worked with ST Microelectronics on NDK-15 (later replaced by NHK-15 from ST Ericsson) I had to merge two kernel trees from two separate teams. Took me 2 days of mangling 20-30MB diffs but got it done. There are people at ST-E which reminded me this during one of Linaro Connects ;D

Also on GUADEC 2007 when we presented new interface for Openmoko phones NDK-15 had to wait for me as no one at stand was able to get it running (U-Boot config needed changes).

But then Intel acquired OpenedHand… The craziest trip of my life was return from London to my parents place. For three months I even had @linux.intel.com email but never used it due to problems with Intel corporate network and Linux (do not ask).

Next was Bug Labs and their BUG device. I cleaned their Poky trees, migrated to latest version and later to use OpenEmbedded directly. Less challenges but I also had few other customers at that time to keep me busy. Some of them were OH customers before and went to me for help.

Time passed, 2010 came. One day Canonical made another attempt to seduce me and this time I decided that it looks like good opportunity so I accepted. Sent BUG 2.0 prototype back to NYC and few weeks later I made crazy train trip to small nowhere near Brussels to meet my new coworkers from NewCore. 1-2 weeks later we got our current name: Linaro.

Total change… From embedded devices to ‘Yes, it is ARM. So what?’ kind as we support(ed) devices powerful enough to run normal desktop software. Many changes for me — from OpenEmbedded where you can (cross) build everything in few hours to Ubuntu packaging where sending package for inclusion into archive meant few hours of buildd queue and then few of build. But I learnt a lot here and met another set of hackers including grey beards ones ;)

And all that because I bought Sharp Zaurus SL-5500 nine years ago…

All rights reserved © Marcin Juszkiewicz
Nine years of embedded Linux was originally posted on Marcin Juszkiewicz website

Few months ago one of my friends borrowed SheevaPlug from me. About two weeks later he gave it back — bricked… I did not had time to play with it so it landed on shelf.

Yesterday I took it and decided to get it back to live. Requirements:

• bricked SheevaPlug (v1.0 without SATA)
• power cable
• mini usb cable
• usb thumb drive
• OpenOCD (“apt-get install openocd”)
• cross compiler (“apt-get install gcc-arm-linux-gnueabi” under Ubuntu)
• U-Boot sources (HEAD of mainline)
• Linux sources (also HEAD of mainline)
• serial terminal (picocom, minicom, screen etc)
• few terminals or terminal multiplexer (I used tmux)

Then:

• Connected power and mini usb cables to SheevaPlug. Desktop recognized usb-serial device as /dev/ttyUSB1.
• Connected to it with serial terminal. Nothing appeared there of course ;)
• Run OpenOCD: “cd /tmp/;sudo openocd -f /usr/share/openocd/scripts/board/sheevaplug.cfg -s /usr/share/openocd/scripts”. SheevaPlug was detected.
• Connected to OpenOCD: “telnet localhost 4444″.
• Built U-boot:

export CROSS_COMPILE=arm-linux-gnueabi-
make mrproper
make sheevaplug_config
make u-boot.kwb

• Copied “u-boot” to “/tmp/uboot.elf” and used “reset;sheevaplug_init;load_image u-boot.elf;resume 0×00600000″ — landed in U-Boot ;)
• There is “sheevaplug_reflash_uboot” macro but it was not working for me. So I used U-Boot to flash itself:

Marvell>> usb start
Marvell>> fatload usb 0:1 0x0800000 u-boot.kwb
Marvell>> nand erase 0x0 0xa0000
Marvell>> nand write 0x0800000 0x0 0xa0000
Marvell>> reset

• Went to Ångström online image builder and built small busybox based image.
• Unpacked tarball into /tmp/initfs, added /dev/ttyS0 node.
• Built Linux kernel:

export CROSS_COMPILE=arm-linux-gnueabi-
make mrproper
make kirkwood_config
make menuconfig (set INITRAMFS_SOURCE to /dev/initfs)
make uImage

• Copied “arch/arm/boot/uImage” to USB thumb drive and inserted it into SheevaPlug.
• Booted image:

Marvell>> set ethaddr 'c0:ff:ee:c0:ff:ee'
Marvell>> set bootargs 'console /dev/ttyS0,115200 rw'
Marvell>> usb start;fatload usb 0:1 0x800000 /uImage;bootm 0x800000

• Landed in nice and small Ångström distribution image ;)
• Went to Ångström online image builder and built console image (task-base based).
• Built Linux kernel (this time without initramfs):

export CROSS_COMPILE=arm-linux-gnueabi-
make menuconfig (unset INITRAMFS_SOURCE)
make uImage

• Copied “arch/arm/boot/uImage” to USB thumb drive and inserted it into SheevaPlug.
• Prepare NAND for UBI:

# mount none /dev -t devtmpfs
# udhcpc eth0
# opkg-cl update
# opkg-cl install mtd-utils
# ubiformat /dev/mtd2
# ubiattach -p /dev/mtd2
# ubimkvol /dev/ubi0 -N rootfs -s 490MiB
# ubiupdatevol /dev/ubi0_0 /media/sda1/angstrom-task-base.ubifs
# mount -t ubifs ubi0:rootfs /media/rootfs
# chown -R root:root /media/rootfs
# cp /media/sda1/uImage /media/rootfs/boot
# sync
# reboot

• Another reconfiguration in U-Boot:

Marvell>> bootargs 'console=ttyS0,115200 rw ubi.mtd=2 rootfstype=ubifs root=ubi:rootfs'
Marvell>> bootcmd 'ubi part nand0,2; ubifsmount rootfs; ubifsload 0x800000 /boot/uImage;bootm 0x800000'
Marvell>> mtdids 'nand0=orion_nand'
Marvell>> set mtdparts 'mtdparts=orion_nand:512k(uboot),4m@1m(kernel),507m@5m(rootfs)'
Marvell>> save
Marvell>> reset

And now my SheevaPlug is operational again. Boots from NAND with latest U-Boot and Linux. There is around 440MB free still on NAND (not counting 4MB partition where kernel was expected to be). I can put it back on shelf now.

The only parts which I needed to compile were U-Boot and Linux kernel. I could skip bootloader and use binary image from Internet but prefer to know what my machines run (and building U-Boot is really easy). Initramfs support in Linux is real live saver as I did not had to play with initrd etc — just build image and boot it. The only problem was that devtmpfs was not auto mounted (even if option in kernel was selected).

I could also use one of those “easy installers” made by PlugComputer community but I found such solutions more complicated (fetching binaries, finding requirements etc) than the one I used.

All rights reserved © Marcin Juszkiewicz
Unbricked my old SheevaPlug was originally posted on Marcin Juszkiewicz website