Booting an old kernel on RPI2

[bob prohaska]

On Mon, Mar 06, 2017 at 10:23:54AM +0100, Ralf Wenk wrote:
> 
> I am having the same problem here.
> It happened during make installworld of r314701. I run make installworld
> while the former kernel r313407  was still active.
> Now both kernels will boot up, but produce the same "out of memory"
> message while going to single- or multi-user.
> So it is not even possible to get a working shell in single-user mode.
> As it first happens during make installworld while still running the
> "old" r313407 kernel I think the cause is not the kernel itself.
> 
> 
As I understand it, sometime before the FreeBSD loader starts up a
division of memory is made between GPU and CPU. There is a config.txt
file containing gpu_mem=64 on my FreeBSD systems, but some of the
Linux literature mentions a file called uEnv.txt, which FreeBSD 
seems not to use (nor does Raspbian, far as I can see). 

I wonder if there might be a u-boot command to
check if the setup routines have become corrupted, leaving too
little memory for the kernel to function, even though it reports
real memory  = 989851648 (943 MB)
avail memory = 957444096 (913 MB)
during the failed boot attempts.


Thanks for reading, and any ideas!

bob prohaska