In the previous tutorial of this series on installing Linux on PDAs, we discussed installing the uClinux distribution on a Handspring Visor. This time, we will take a look at a Linux distro specifically designed for the VTech… Helio handheld device.

Some of you may be wondering what a Helio PDA is. The Helio normally uses a proprietary OS made by VTech called the VT-OS. Helio PDAs are not commonly found devices anymore, but that's OK, because you should be able to pick one up for less than $100 USD second-hand. If you can find one, you will have a 75MHz handheld with 8M of RAM and 2M Flash ROM with a 32-bit RISC processor has a 160 x 160 pixel backlit LCD display with a 1024 x 1024 cell touchpad, integrated audio record/playback, and both standard and high-speed serial ports. (Further details on the Helio are available in this LinuxDevices.com device profile.)

VTech even provides an SDK and emulator that allows developers to continue creating applications for this discontinued device.

PicoLinux

The distribution of Linux we will be using is called PicoLinux, a Linux port for handheld devices based on PicoGUI. PicoGUI is an open-based user interface for embedded device architectures with ports for a wide variety of devices, including the Sega Dreamcast video game console and Sharp Zaurus handheld device.

WARNING

In order to flash your Helio with a new OS, you will lose all information stored on it, and possibly run the risk of permanently destroying the device forever. (If you're lucky enough to find one, it will probably be listed at a discounted price, so it shouldn't matter either way.) While there is only a slight chance of this happening, the chance still exists. Be forewarned, and take a moment to read through these precautions:

• Back up ALL of the contents of your device.
• Create or download a backup ROM image for the VT-OS. (You can find information on how to create backup ROMs here)
• Be prepared to violate all conditions of your warranty.
• I take no responsibility for your actions.

Installation Instructions

In order to replace your existing VT-OS with PicoLinux, you will need to be running Windows 95, 98 or NT, because the 'dt.exe' application used to flash the ROM will not work properly on Windows 2000 or higher. My advice is to use a Linux box to do your transfer. In case one is not available, I will also show you how to use an older Windows OS or DOS.

Download the following files:

• dt-0.1.tar.gz (for Linux)
• dt-fltk-win32.zip (for Windows)
• picolinux-helio.bin

For my experiment, I used a machine running RedHat Linux 7.2. The whole process took less than 10 minutes, and I was able to try out several versions of the PicoLinux build before I settled on the one listed above for download. With a little research, you may be able to find other builds or create your own.

To begin, you will need to get to the BootLoader screen on your Helio. This will prepare it for OS replacement. Follow these steps:

• Insert a paperclip or use the inside of your stylus to press the reset button on the back while pressing the 'On' button for 2 seconds
• Release both buttons simultaneously
• Press the 'Up' button on the side and 'On' button and hold both for 6 seconds
• Release both buttons and then press the 'Down' button on the side
• You should now be in the BootLoader screen

Don't worry if it doesn't work the first couple of times. You will need to be patient; it helps to count aloud as you follow the steps.

Place the device into its cradle and execute the DT application. Depending on your OS, you have the option of running it from DOS, from Windows or from a terminal window in Linux.

• Windows and DOS — If there is not a c:helio directory, create it. You will need to copy the 'loader.sre' file to that directory before running dt.exe. Once you have created the directory and moved the sre file, either open up dt.exe, or open a command terminal and go to the directory where dt.exe exists, and run it. You will need to choose the pre-compiled Linux binary file and select the appropriate Comm port. Default should be Comm 1. Once the file transfer begins, you will need to wait 4 to 6 minutes for it to complete and generate the “Write Check Complete!” message.

• Linux — Although the steps may a bit more complicated on Linux machines, the results are far more reliable. First you will need to execute tar xvzf dt-0.1.tar.gz. Next, cd into the 'dt' directory and then su to root to access the serial port. Run this line: “./dt /dev/ttyS0 picolinux-helio.bin 0x10000” to begin flashing the Helio. Wait.

Using PicoLinux

Once you have completed the flash procedure, you will need to reset your device. Booting PicoLinux should take a few seconds, and then you will be taken to the calibration screen, similar to PalmOS. After calibration, you should see the PicoLinux desktop.

Don't expect a lot of applications. You will have a basic calculator, pTerm, a simple 'Blackout' game, a few system utilities, and some demo application samples for developers. It's not much, but the door has now been opened for you to build and install whatever you want onto your new, handheld Linux device.

And if you're really confident in your handheld device OS replacement abilities, stay tuned for our next installment, where we will *attempt* to replace the iPAQ's WinCE with Linux, also.

So go nuts, and feel free to email me if you have any questions.

Copyright © 2002 AnywhereYouGo.com. All rights reserved. Reproduced by LinuxDevices.com with permission.

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About the author: Jay Staton works as a Staff Writer for AnywhereYouGo.com, a wireless technology community portal website operated by Hewlett-Packard. Staton has been a WAP developer for the past 2 years, and spends his free time trying to convince his wife how much he needs the latest and greatest wireless devices.

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This article was originally published on LinuxDevices.com and has been donated to the open source community by QuinStreet Inc. Please visit LinuxToday.com for up-to-date news and articles about Linux and open source.