utgg wrote: 
> No it's not. It is in embedded rom.

Yes and no. The RPi designers did quite some cost-cutting measures. The
first-stage bootloader, in RPi terminology, is indeed in ROM, and can't
be updated, but the only thing that that code can do is load the second
stage (bootcode.bin) from the boot partition on the SD card - so a RPi
can not boot from the network or USB stick. Not only that, but neither
the first nor the second stage actually run on the main CPU - they run
on the GPU (graphics processor). The second stage loads the third-stage
bootloader (start.elf) from the SD card. 

So the second stage bootloader on a RPi corresponds to a traditional
basic bootloader, and *can* be updated. The third stage corresponds to a
PC BIOS, and has actual hardware settings (config.txt), and can also be
updated. 

As the fourth stage, the actual kernel (kernel.img) gets loaded, and is
the first code to actually run on the main CPU.

Anyway, yes, all the user-upgradeable parts live on the SD card, and the
stuff on the main board can not be updated.



"To try to judge the real from the false will always be hard. In this
fast-growing art of 'high fidelity' the quackery will bear a solid gilt
edge that will fool many people" - Paul W Klipsch, 1953
------------------------------------------------------------------------
Julf's Profile: http://forums.slimdevices.com/member.php?userid=42050
View this thread: http://forums.slimdevices.com/showthread.php?t=104698

_______________________________________________
discuss mailing list
[email protected]
http://lists.slimdevices.com/mailman/listinfo/discuss

Reply via email to