easiest way to stop u-boot from searching for further uEnv.txt files?

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 ...
Checking if client_ip is set ...
Checking for: /boot.scr ...
Checking for: /boot/boot.scr ...
Checking for: /boot/uEnv.txt ...
gpio: pin 55 (gpio 55) value is 1
33 bytes read in 42 ms (0 Bytes/s) <-- ... and there
Loaded environment from /boot/uEnv.txt
... snip ...

  for the purposes of simplicity, i would prefer that u-boot consult
nothing beyond the SD card ... without reconfiguring and rebuilding
u-boot, what is the easiest way to do that? thanks.

rday

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.

Checking if client_ip is set …
Checking for: /boot.scr …
Checking for: /boot/boot.scr …
Checking for: /boot/uEnv.txt …
gpio: pin 55 (gpio 55) value is 1
33 bytes read in 42 ms (0 Bytes/s) ← … and there
Loaded environment from /boot/uEnv.txt
… snip …

for the purposes of simplicity, i would prefer that u-boot consult
nothing beyond the SD card … without reconfiguring and rebuilding
u-boot, what is the easiest way to do that? thanks.

Your best option is just to really rebuild mainline without my patch.

Regards,

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

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.

Well yeah, bootm/bootz/etc...

  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.

Sorry, i bullet proofed u-boot too much for you..

Regards,

challenge accepted. :slight_smile:

rday

Oh, also on failure, if you have the usb-slave port connected, eMMC
should pop up as a flash drive. :wink:

Regards,