mjhjmtu

I am running u-boot on a Beaglebone Black custom install, and have modified ./include/configs/am335x_evm.h to set the default bootdelay to 0, which was working well when I was loading my kernel and device tree off of a fat partition. But I switched partition 1 from fat to ext4, and change the fatload statements in my uEnv.txt to ext4load. Everything works just as before, except now I'm back to having a 2 second bootdelay. I don't understand why switching partition types would cause this.

Does anybody know how I can recompile u-boot to set bootdelay back to 0 in the case of me using ext4 boot partition?

Alternatively, I suppose I could figure out how to get saveenv working. Currently it gives:

=> saveenv
Saving Environment to FAT... MMC: no card present
** Bad device mmc 0 **
Failed (1)

But honestly I'd rather just change the default at compile time.

Download the ARM cross-compiler GCC on your PC.

wget -c https://releases.linaro.org/components/toolchain/binaries/6.4-2017.11/arm-linux-gnueabihf/gcc-linaro-6.4.1-2017.11-x86_64_arm-linux-gnueabihf.tar.xz
tar xf gcc-linaro-6.4.1-2017.11-x86_64_arm-linux-gnueabihf.tar.xz
export CC=**/path to**/gcc-linaro-6.4.1-2017.11-x86_64_arm-linux-gnueabihf/bin/arm-linux-gnueabihf-

Make sure you have the correct path.It should be from the root, something like this /home/username/path to gcc-linaro/bin/arm-linux-gnueabihf-

Test Cross Compiler:

$CCgcc --version

You should see this on your terminal if you have the correct path:

arm-linux-gnueabihf-gcc (Linaro GCC 6.4-2017.11) 6.4.1 20171012
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Download u-boot

git clone https://github.com/u-boot/u-boot
cd u-boot/
git checkout v2018.01 -b tmp

Get the patches (Needs internet connection)

wget -c https://rcn-ee.com/repos/git/u-boot-patches/v2018.01/0001-am335x_evm-uEnv.txt-bootz-n-fixes.patch
wget -c https://rcn-ee.com/repos/git/u-boot-patches/v2018.01/0002-U-Boot-BeagleBone-Cape-Manager.patch
wget -c https://raw.githubusercontent.com/RobertCNelson/Bootloader-Builder/master/patches/v2018.03-rc1/0002-NFM-Production-eeprom-assume-device-is-BeagleBone-Bl.patch

Apply patches to u-boot

patch -p1 < 0001-am335x_evm-uEnv.txt-bootz-n-fixes.patch
patch -p1 < 0002-U-Boot-BeagleBone-Cape-Manager.patch
patch -p1 < 0002-NFM-Production-eeprom-assume-device-is-BeagleBone-Bl.patch

Configure and Build

make ARCH=arm CROSS_COMPILE=$CC distclean
make ARCH=arm CROSS_COMPILE=$CC am335x_evm_defconfig

Now in the u-boot folder there will be .config file you can edit and change the bootdelay parameter.
Build

make ARCH=arm CROSS_COMPILE=$CC

Attach the SD card to the computer and run ‘lsblk’ to find out the id of the SD card. In my case the id was ‘sdb’

Install:

export DISK=/dev/sdb
sudo dd if=./MLO of=$DISK count=1 seek=1 bs=128k
sudo dd if=./u-boot.img of=$DISK count=2 seek=1 bs=384k