iMX6 OpenRex Ultra U-Boot

U-Boot is a bootloader responsible for hardware initialization, loading and booting Linux kernel. It is also used for SBC flashing.

Build

Set toolchain

Export toolchain variables for every related terminal session.

Initial steps

Create working directory

mkdir -pv ~/workdir/imx6/bootloader/

U-Boot v2015.04

Download and extract source code

cd ~/workdir/imx6/bootloader/
git clone -b uboot-imx-v2015.04 --single-branch https://github.com/voipac/uboot-imx uboot-imx-v2015.04-rex
cd uboot-imx-v2015.04-rex

Compile

Output file is called u-boot.imx. All the compiled images are intended for production usage.

Compile for SD3 and Linux/Yocto

cd ~/workdir/imx6/bootloader/uboot-imx-v2015.04-rex
make distclean
make mx6openrexbasic_config
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi-
cp -av u-boot.imx /srv/tftp/imx6/u-boot-imx6-openrexbasic.imx

How to Flash a new version

Flash into SPI Flash using U-Boot

setenv ipaddr 192.168.0.150
setenv serverip 192.168.0.1
mw.b 0x10800000 0xFF 0x80000
tftp 0x10800000 imx6/u-boot-imx6-openrex*.imx
if sf probe 2:2; then sf erase 0x0 0x80000;sf write 0x10800000 0x400 0x7fc00; fi

Flashing log:

U-Boot 2015.04-gfd6325c-dirty (Mar 11 2017 - 23:09:03)

CPU:   Freescale i.MX6SOLO rev1.1 at 792 MHz
CPU:   Temperature 34 C
Reset cause: POR
Board: MX6 OpenRex - basic
I2C:   ready
DRAM:  512 MiB
PMIC:  PFUZE100 ID=0x10
MMC:   FSL_SDHC: 0
SF: Detected SST26VF032B with page size 256 Bytes, erase size 4 KiB, total 4 MiB
In:    serial
Out:   serial
Err:   serial
Net:   FEC [PRIME]
Normal Boot
Hit any key to stop autoboot:  0 
OpenRex U-Boot > setenv ipaddr 192.168.1.150
OpenRex U-Boot > setenv serverip 192.168.1.1
OpenRex U-Boot > mw.b 0x10800000 0xFF 0x80000
OpenRex U-Boot > tftp 0x10800000 imx6/u-boot-imx6-openrexbasic.imx
Using FEC device
TFTP from server 192.168.1.1; our IP address is 192.168.1.150
Filename 'imx6/u-boot-imx6-openrexbasic.imx'.
Load address: 0x10800000
Loading: #######################
         2.8 MiB/s
done
Bytes transferred = 334848 (51c00 hex)
OpenRex U-Boot > sf probe 2:2;sf erase 0x0 0x80000;sf write 0x10800000 0x400 0x7fc00
SF: Detected SST26VF032B with page size 256 Bytes, erase size 4 KiB, total 4 MiB
SF: 524288 bytes @ 0x0 Erased: OK
SF: 523264 bytes @ 0x400 Written: OK
OpenRex U-Boot >

Configure

Manually erase configuration

OpenRex U-Boot > sf probe 2:2       
SF: Detected SST26VF032B with page size 256 Bytes, erase size 4 KiB, total 4 MiB
OpenRex U-Boot > sf erase 0x80000 0x2000
SF: 8192 bytes @ 0x80000 Erased: OK
OpenRex U-Boot > reset

Manual boot options

Manually boot from SPI3

mw.l 0x020d8040 0x2A000030; mw.l 0x020d8044 0x10000000; reset

Manually boot from SD2

mw.l 0x020d8040 0x00002840; mw.l 0x020d8044 0x10000000; reset