On Tue, 10 Feb 2015, Robert Nelson wrote:
>
>
> On Feb 10, 2015 5:03 AM, "Robert P. J. Day" <[email protected]> wrote:
> >
> >
> > putting together a student lab for building u-boot for the BBB
> > (which i'll post shortly for anyone who's interested), and just
> > noticed that when i boot from a minimally-populated SD card (that is,
> > nothing but MLO and u-boot.ing and an empty uEnv.txt), u-boot still
> > insists on checking out possible partitions in eMMC, which i *don't*
> > want it to do.
> >
> > here's snippets of the output on the console. first, i can see where
> > it consults the uEnv.txt file in the VFAT partition, which is
> > deliberately empty:
> >
> > ... snip ...
> > mmc0 is current device
> > gpio: pin 54 (gpio 54) value is 1
> > Checking for: /uEnv.txt ...
> > reading uEnv.txt <-- good
> > 0 bytes read in 3 ms (0 Bytes/s)
> > ... snip ...
> >
> > but further down, u-boot runs off to eMMC and pulls in uEnv.txt files
> > there as well:
> >
> > ... snip ...
> > switch to partitions #0, OK
> > mmc1(part 0) is current device
> > gpio: pin 54 (gpio 54) value is 1
> > Checking for: /uEnv.txt ...
> > reading uEnv.txt
> > 26 bytes read in 3 ms (7.8 KiB/s) <-- there ...
> > gpio: pin 55 (gpio 55) value is 1
> > Loaded environment from uEnv.txt
> > Importing environment from mmc ...
> > Checking if uenvcmd is set ...
>
> Your answer is here: ^
>
> Define uenvcmd to anything and it'll stop dead.
really? i already tried that, all it does is "run uenvcmd", but
unless that command invokes something like a "bootm", processing will
still continue. "bootcmd" has at least a couple places where "uenvcmd"
is run, and bootcmd processing carries on after that.
i guess another way to ask what i'm after is i want a way to take
eMMC totally out of the boot process in a non-destructive way.
rday
--
========================================================================
Robert P. J. Day Ottawa, Ontario, CANADA
http://crashcourse.ca
Twitter: http://twitter.com/rpjday
LinkedIn: http://ca.linkedin.com/in/rpjday
========================================================================
