Few weeks ago I got an opportunity to buy HP 620LX handheld PC. It is a small device based on Hitachi SH7709 SH-3 ~75MHz SoC with 16MB RAM, one CompactFlash slot and one CardBus (PCMCIA) slot. It also has an option to connect serial cable (cable comes with the device). The default operating system is Windows CE 2.0 (or 2.11 if you are lucky to find the ROM upgrade).

System was untested and didn’t have original power adapter, however was packaged in original box with most accessories available. Fortunately, the system booted successfully using 12V 1A adapter (the original adapter provides 2A if I am not mistaken), giving me an opportunity to test NetBSD on it. HP 620LX is supported by hpcsh port, which aims to run on various handheld devices based on SH-3/4 SoCs.

Installation process is not completely trivial on this type of devices. One important point is that booting NetBSD will completely reset Windows CE device, loosing all configuration and data, thus backup is required, if it contains something important to the user (not in my case). There’s no sysinst(8) support, CF memory card should be prepared in advance on another NetBSD system. The instructions are available here, even more detailed instructions can be found here (thanks @uwe for pointing this document in the mailing list). To make the long story short: two partitions should be prepared: one DOS partition of the “small” size (20-30MB), and at least one FFS partition for NetBSD root partition. The DOS partition needs to include kernel file and a boot loader application. Distribution sets should be extracted to the NetBSD partition(s) (at least base, etc IMHO), and initial configuration can be done for /etc/rc.conf, /etc/fstab, etc.

Once everything is ready, hpcboot.exe needs to be executed from Windows CE. Choosing the right bootloader executable appeared to be the first challenge though. Installation directory in the port’s distribution contains sh3-hpcboot.exe and sh4-hpcboot.exe with seemingly the obvious choice for SH-3 based device. The caveat is that the binary is build for Windows CE 2.11 and above, and it fails to run on Windows CE 2.0. My initial fear was that I would need to build one myself with the right tools. Fortunately, I found one in the NetBSD code instead. It is uuencoded, thus should be decoded first by running command uudecode -o hpcboot.exe hpcboot200.exe.uue. The bootloader program allows to choose the device and several boot flags, and after few seconds NetBSD boot messages appear on the screen. On initial boot I faced the second issue, related to disk labels. The main reason was that my FFS partition was not labeled as wd0a. It appeared to be an easy fix sudo disklabel -e /dev/rsd3 (rsd3 may differ on your device) and just edit and save label from f->a (in my case) in the opened editor. Soon after I had a properly booting system and could successfully login to the system. Here the final configuration can be performed, like creation of users, setting the passwords, etc.

What’s next? First of all, I plan to add hpc200.exe to distribution files. After, I would like to enable some of my pcmcia devices (wifi card and SATA card), test network, test serial, and just to keep port a little bit more alive! Time will tell.

Enjoy dmesg below for now: