Re: Pi2 bootcode.bin puzzle

bp@www.zefox.net wrote:

Theo <theom+news@chiark.greenend.org.uk> wrote:

bp@www.zefox.net wrote:

Can bootcode.bin pick up any parameters (other than noting the
presence of a timeout file) from any files placed on the microSD?

 
No idea, but one problem I've had in the past is that USB devices can take a
while to initialise, and it varies quite a bit between devices.  This could
be a reason why boots will sometimes fail - especially with eg spinning HDD.
 
Often it was necessary to add an explicit delay so that system didn't try to
read them before they were ready.  I think on Linux the kernel cmdline
options were 'rootwait' and 'rootdelay' but I don't know if bootcode.bin has
any kind of setting like that.

 
I've tried with and without the presence of a timeout file on the
fat32  partition of the microSD, far as I can tell it makes no
difference once things start going wrong. I do use it out of habit.
 
Does bootcode.bin pay any attention to config.txt? I thought it did,
but am not sure it has any effect on USB mass storage boot. The docs
say don't use any extra files on the fat32 partition.

I believe that config.txt is consumed by the GPU-side firmware, which is
start*.elf.  bootcode.bin is just enough to be able to load start.elf
and config.txt from storage.  I'd guess that if that storage is USB, it's
too early to have read config.txt.

Theo