Using Debian Community Filesystem¶

Guide to convert existing debian sd card to boot on MTK¶

This guide was done using the following image:
https://debian.beagleboard.org/images/bone-debian-8.6-lxqt-4gb-armhf-2016-11-06-4gb.img.xz
This image used kernel tag 4.4.30-ti-rt-r64 and so attached device tree was built for this kernel. It will likely only need minor modifications to work with similar 4.4 kernels.

• Update u-boot
  • Build CL u-boot with mityarm335x_maker defconfig. https://support.criticallink.com/redmine/projects/armc8-platforms/wiki/Das_U-Boot_Port#Building-u-Boot
    MLO
    u-boot.img
    

    U-Boot 2013.10-00069-gf9dd46dead39
    

  • The newer debian images have u-boot installed directly in block device, not in seperate boot partition. So we need to use dd to update it.
    

    sudo dd if=MLO of=/dev/sdi count=1 seek=1 conv=notrunc bs=128k
    sudo dd if=u-boot.img of=/dev/sdi count=2 seek=1 conv=notrunc bs=384k
    

  • The older debian images with the seperate boot partition should be easier to update by replacing the MLO/u-boot.img file in the boot partition.
• Modify /boot/uEnv.txt file
  • Specify the maker board dtb file
    

    dtb=am335x-mitysom-maker.dtb
    

  • Alternative: The bonegreen dtb can be used to get a booting device, but ethernet and cape detection won't work. Likely other things as well.
    

    dtb=am335x-bonegreen.dtb
    

  • Add rootfs type as this variable is missing in our u-boot
    

    mmcrootfstype=ext4 rootwait
    

• Copy dtb file to sd card /boot/dtbs/4.4.30-ti-r64/
• Boot device
• Optional: To shut down lightdm gui and free up memory.
  

  root@beaglebone:~# systemctl stop lightdm.service
  

• Flash board eeprom to get cape manager to work
  

  root@beaglebone:~# dd if=/opt/scripts/device/bone/bbb-eeprom.dump of=/sys/bus/i2c/devices/0-0050/eeprom
  root@beaglebone:~# hexdump -e '8/1 "%c"' /sys/bus/i2c/devices/0-0050/eeprom
  �U3�A335BNLT������������*
  �U3�A335BNLT������������*
  �U3�A335BNLT������������*
  �U3�A335BNLT������������*
  �U3�A335BNLT������������*
  �U3�A335BNLT������������*
  �U3�A335BNLT������������*
  �U3�A335BNLT������������*
  root@beaglebone:~# 
  

• Reboot

Using a BB-BONE-LCD7-01-00A3.dts compatible cape¶

• Copy dtb overlay file to sd card /boot/dtbs/4.4.30-ti-r64/
  Created a "-overlay" device tree which disables spi, hdmi, and audio as they conflict with the LCD cape overlay. This was based off the differences between am335x-boneblack.dts and am335x-boneblack-overlay.dts.
  am335x-mitysom-maker-overlay.dts
  am335x-mitysom-maker-overlay.dtb
• Update /boot/uEnv.txt to use overlay dtb
  

  dtb=am335x-mitysom-maker-overlay.dtb
  

• Boot
• Verify cape manager found LCD
  

  root@beaglebone:~# dmesg | grep bone_capemgr
  [    3.730507] bone_capemgr bone_capemgr: Baseboard: 'A335BNLT,\xffffffff\xffffffff\xffffffff\xffffffff,\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff'
  [    3.737956] bone_capemgr bone_capemgr: compatible-baseboard=ti,beaglebone-black - #slots=4
  [    3.752557] bone_capemgr bone_capemgr: slot #0: '4D 7.0 LCD CAPE- 4DCAPE-70T     ,00A3,4D SYSTEMS      ,BB-BONE-LCD7-01'
  [    3.802226] bone_capemgr bone_capemgr: slot #1: No cape found
  [    3.846228] bone_capemgr bone_capemgr: slot #2: No cape found
  [    3.890227] bone_capemgr bone_capemgr: slot #3: No cape found
  [    3.896370] bone_capemgr bone_capemgr: initialized OK.
  [    3.939085] bone_capemgr bone_capemgr: slot #0: dtbo 'BB-BONE-LCD7-01-00A3.dtbo' loaded; overlay id #0