Re: Pi2 bootcode.bin puzzle

bp@www.zefox.net wrote:

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

bp@www.zefox.net wrote:

 
AIUI, config.txt sets up the Pi, cmdline.txt furnishes
runtime arguments to the kernel when that kernel is
linux. If this isn't true somebody please correct me!

 
Does it show the FreeBSD beastie text-mode screen?
https://docs.freebsd.org/images/books/handbook/virtualization/qemu-freebsd02.png
 
In which case you can probably set things up in loader.conf:
https://docs.freebsd.org/en/books/handbook/boot/index.html#boot-loader
 
the same way you do on x86.

 
Might it be possible to let the machine boot from microSD to the
loader prompt, next re-load the kernel from the USB drive, then
start the new kernel and finally mountroot from USB?
 
That seems too easy. I must be missing something.

Well, it's less easy than I thought, but it does seem to work.

The method is to interrupt boot just before the kernel starts.
Next, unload the kernel, set the currdev to disk0s2a, set
the root device to da0s2a, load the kernel again (from the
new root device and boot.

Setting currdev and rootdev can be done in /boot/loader.conf
on the microSD's FreeBSD, I've asked on the freebsd-arm mailing
list where the unload and load commands should go.

There are still some problems with usb disk discovery failing,
but this is a big improvement.

Thank you Theo!

bob prohaska