Linux As Bootloader

1
Linux As Bootloader

• Status Update Fall 2003

2
What is LAB?

• LAB Linux As Bootloader
• Also known as bootldr-ng
• Using Linux kernel code to load an operating
  system
• Deprecates original OHH bootloader

3
iPAQ Bootloader history

• Many bootloaders for iPAQ
• Parrot
• Can only load WinCE/PPC, however comes default on
  all iPAQs.
• OHH Bootloader
• Standard QNX/Linux/BSD bootloader for handheld
  devices other than Sharp Zaurus.
• LAB
• Next generation bootloader for Linux-supported
  devices.

4
Why LAB?

• OHH Bootloader is just one more application to
  port to a new device
• Linux has many commonly used features that would
  be beneficial to a bootloader, however difficult
  to port to OHH
• USB
• MMC/SD
• File-system modules

5
LAB Implementation

• Option in kernel config
• Gets called instead of execing /sbin/init
• Eliminates userland problem
• No initrd needed
• Also has assembler stubs in head-processor.S to
  initialize RAM, GPIOs, etcetera

6
Commands

• Commands in LAB much like old bootloader commands
• UI code direct port
• Can build commands as modules and load w/ insmod
  command
• Also have copy API Examples
• boot copy flash0 fs/ramfs/flashimage
• boot copy ymodem flash1

7
LAB Status

• Expected to have LAB booting standalone on PXA
  devices and self-reflashing by end of today
• Command API fully functional
• Copy API fully functional
• USB support just ironing out kinks
• Known to push in excess of 25KB/s over ymodem
  (!!)
• Expected to be able to boot kernel Real Soon Now

8
Conclusion

• Linux As Bootloader brings us one step closer to
  having Linux be self-booting on many more devices
• Expected possibly for Familiar 0.8 release
• Enjoy!
• Linux As Bootloader
• Fall 2003
• Joshua Wise