Saturday, August 09, 2008

Booting OSWA on Eee PC with SD flash

These are some notes for making a bootable SD flash card for my Eee PC from the "OSWA Assistant" bootable CD.

A bootable or "live" CD is a popular way of distributing hacking tools. You just put the CD into any computer and boot from it (instead of your normal hard disk). You get a Linux desktop and pointers to a list of common programs. The most famous of these is probably the "Backtrack CD.

Another one for wireless auditing is "OSWA Assistant". I've never used it before, but they were handing out CDs at BlackHat 2008 Vegas.

The computer I want to use for this Asus Eee 2G Surf", a $299 disposable laptop. Everybody should probably have a handful of these around to play with.

The problem with the Eee PC is that it doesn't have a CD-ROM drive, so I can't boot the OSWA CD. However, it does have three USB ports and one SD flash port. The SD port is especially nice for booting. You can get 2-gig SD flash cards for $7; they are hella cheap.

To make a bootable SD card from the CD, I went through the following steps.

Step 1: I copied all the files to the SD card. I first put the SD flash card into my Windows PC which became the "D:" drive. I downloaded the latest oswa-assistant.iso image from the OSWA website, opened it in WinRAR on my Windows PC, and extracted all the files to the "D:" drive. You can use pretty much any tool for extracting the files, I just happened to have WinRAR handy. I didn't even know that WinRAR could extract files from ISOs - I just assumed that is the sort of thing that WinRAR ought to be able to do.

Step 2: I needed to make the flash bootable. Most bootable CDs use a tool called "isolinux" to go through the boot process. There is a sibling tool called "syslinux" for making bootable Linux flash devices, such as USB flash or SD flash. I downloaded the syslinux archive, extracted to "C:\syslinux". I opened a command prompt, went to "C:\syslinux\win32" and ran "syslinux.exe -ma D:" to make the SD card bootable.

Step 3: I had to change the "isolinux" configuration to a "syslinux" one. I renamed the "D:\boot\isolinux" directory to a "D:\boot\syslinux" directory instead. I also had to rename the "isolinux.cfg" file in that directory to "syslinux.cfg".

Step 4: I had to configure the Eee PC to boot from SD, otherwise it will boot from its own hard disk. When the system boots, I hit "F2" to go into the BIOS configuration, and change the boot order so that Removable Devices are at the top of the list.

At this point, the system boots. However, there several problems. First, it complains "You passed an undefined mode number.", which refers to the fact that it doesn't understand something about the text mode screen. Simply hit to continue.

When it reaches "Starting udev hot-plug hardware detection...", it will hang for a while with the message "Starting udev hot-plug hardware detection… udevd-event[2706]: run_program: '/sbin/modprobe' abnormal exit". Don't worry, it will continue on with the boot process after about 5 minutes. It's a bit annoying though. I wish I knew what was failing.

Step 5: There was one fatal error. X Windows hangs looking for an AGP card. The In order to fix this, I had to edit the "D:\boot\syslinux\syslinux.cfg" file and put "noagp" on the second line:
APPEND ramdisk_size=100000 init=/etc/init lang=us apm=power-off vga=791 initrd=minirt.gz nomce loglevel=0 quiet BOOT_IMAGE=oswa noagp

Step 6: Profit!


Unknown said...

there is now a link on oswa assistant website which shows instruction how to create liveusb version from the livecd image.
following the instructions and using the simple windows dos tool from the link is much more simple and direct for me becos i dont have to edit files like above.
i try the method shown in the link using my kingston compact flash 4gb and it work great - i only need to plug in pendrive, cf, sd or whatever flashmemory into standard usb card reader under windows and then run the dos tool which take care of everything. much easier! but just make sure your laptop can support boot from flashmemory...

Unknown said...


Have you been able to get the OSWA Assistant to recognize the Eee PC's wireless NIC?

Also,thank you for this tutorial, I've extended it a bit on my blog.

Stephen Kapp said...


Been having the same problems with the Wifi card in the Eee PC. Although I have been considering replacing the Wifi in there with something less problematic as I had problems with it and Backtrack too.

Anonymous said...

there is now a link on oswa assistant website which shows instruction how to create liveusb version from the livecd image.

Blowed if I can find it!

Anonymous said...

1. Battery Life - It really is that good. I can get a real world value of 7.5 to 8 hours with the WLAN on under the power saving mode. I can't even see a difference with the performance when in this mode.
2. LED-lit screen - I was expecting a basic screen that didn't look particularly great. I was surprised with the look of it, even at the low, netbook standard resolution.
3. Keyboard - The so-called chiclet keys are very comfortable, and the placement of the shift key in the correct spot really separates this model from the rest.

1. Windows XP - Yeah, I know. Most would say this is a pro. However, I passed the XP life-cycle on desktops and I'm now having to learn the intricacies of this OS. I wish I could have have them put the Windows 7 beta on it before shipping because I did not get it in time to download, but I digress.
2. Performance - Not technically a con, but I expected a little more of a boost from the bus increase to 667 Mhz. Still, it serves its purposes as a netbook, and the upcoming performance boost in Intel's chipset will probably decrease battery life by 2-3 hours.