#embedded #openembedded #beaglebone #u-boot #reversing

README.md

In order to get started quickly (source) you can build an image for qemu-x86 with the following commands

# apt-get install gawk wget git-core diffstat unzip texinfo gcc-multilib \
    build-essential chrpath libsdl1.2-dev xterm
$ git clone git://git.openembedded.org/openembedded-core oe-core && cd oe-core
$ git clone git://git.openembedded.org/bitbake bitbake
$ git checkout fido && cd bitbake && git checkout 1.26 && cd -
$ source ./oe-init-build-env
$ bitbake core-image-minimal

The final image will be at the path <build dir>/tmp-glibc/deploy/images/qemux86. The next step is run the built image

oe-core/build $ (fido) runqemu qemux86 core-image-minimal ext4
Assuming core-image-minimal really means /opt/openembedded/oe-core/build/tmp-glibc/deploy/images/qemux86/core-image-minimal-qemux86.ext4

Continuing with the following parameters:
KERNEL: [/opt/openembedded/oe-core/build/tmp-glibc/deploy/images/qemux86/bzImage-qemux86.bin]
ROOTFS: [/opt/openembedded/oe-core/build/tmp-glibc/deploy/images/qemux86/core-image-minimal-qemux86-20151008151916.rootfs.ext4]
FSTYPE: [ext4]
Setting up tap interface under sudo
Acquiring lockfile for tap0...
Running qemu-system-i386...
/opt/openembedded/oe-core/build/tmp-glibc/sysroots/x86_64-linux/usr/bin/qemu-system-i386 -kernel /opt/openembedded/oe-core/build/tmp-glibc/deploy/images/qemux86/bzImage-qemux86.bin -net nic,vlan=0 -net tap,vlan=0,ifname=tap0,script=no,downscript=no -cpu qemu32 -hda /opt/openembedded/oe-core/build/tmp-glibc/deploy/images/qemux86/core-image-minimal-qemux86-20151008151916.rootfs.ext4 -show-cursor -usb -usbdevice wacom-tablet -vga vmware -no-reboot -m 256 --append "vga=0 uvesafb.mode_option=640x480-32 root=/dev/hda rw mem=256M ip=192.168.7.2::192.168.7.1:255.255.255.0 oprofile.timer=1 rootfstype=ext4 "

It's possible to login as root (wo password).

Toolchain

It's possible to build a toolchain

$ bitbake meta-toolchain

that produces an installer in <build dir>/tmp-glibc/deploy/sdk.

Kernel

Exists a recipe named virtual/kernel; if you want to clean it

$ MACHINE=beaglebone bitbake -c clean virtual/kernel

beaglebone.md

You can build a complete system with this instruction or create an image using this

Home page | Wiki | Android

The uENV.txt file is in the FAT partition not in the /boot directory, the BOOT button decides only if the system will use the file from the eMMC or from the SD (source).

##Links

• https://www.eewiki.net/display/linuxonarm/BeagleBone+Black
• http://icculus.org/~hendersa/android/

U-Boot

• http://www.twam.info/hardware/beaglebone-black/u-boot-on-beaglebone-black

Android

It's possible to build Android using the following mannifest

repo init -u git://gitorious.org/rowboat/manifest.git -m rowboat-jb-am335x.xml

and the command

make TARGET_PRODUCT=beagleboneblack OMAPES=4.x droid -j8

source: https://eewiki.net/display/AOA/BeagleBone+Black

Kernel

$ git clone https://github.com/RobertCNelson/bb-kernel.git && cd bb-kernel
$ git checkout --track origin/am33x-v3.18
$ ./build_kernel.sh

Serial pinout

From the original wiki

J1 GND
J4 RX
J5 TX

The connection is

• Baud 115,200
• Bits 8
• Parity N
• Stop Bits 1
• Handshake None

With the Bus Pirate remember to set select normal as output type

(1)>
Select output type:
 1. Open drain (H=Hi-Z, L=GND)
 2. Normal (H=3.3V, L=GND)

http://codechief.wordpress.com/2013/11/11/beaglebone-black-serial-debug-connection/

HDMI issues

root@beaglebone:/sys/class/drm/card0/card0-HDMI-A-1# xrandr --verbose                                                                                                                        
Screen 0: minimum 320 x 200, current 1280 x 720, maximum 2048 x 2048                                                                                                                         
HDMI-0 connected 1280x720+0+0 (0x42) normal (normal left inverted right x axis y axis) 474mm x 296mm                                                                                         
       Identifier: 0x40                                                                                                                                                                      
       Timestamp:  1523547016
       Subpixel:   unknown
       Gamma:      1.0:1.0:1.0
       Brightness: 1.0
       Clones:
       CRTC:       0
       CRTCs:      0
       Transform:  1.000000 0.000000 0.000000
                   0.000000 1.000000 0.000000
                   0.000000 0.000000 1.000000
                  filter:
       EDID:
               00ffffffffffff000469f12201010101
               20130103802f1e782e78f5a655489b26
               125054bfef80b30081809500950f9040
               714f0101010121399030621a274068b0
               3600da281100001c000000ff0039384c
               4d56443030343433360a000000fd0038
               4b1f5111000a202020202020000000fc
               00415355532d4c5332323148ffff01ff
               02031e764b909f859484930312010716
               230907078301000065030c000000023a
               801871382d40582c9600da2811000018
               023a80d072382d40102c4580da281100
               001e011d8018711c1620582c2500da28
               1100009e011d80d0721c1620102c2580
               da281100009e011d00bc52d01e20b828
               5540da281100001e00000000000000dd
  1280x720 (0x41)   74.2MHz +HSync +VSync
        h: width  1280 start 1720 end 1760 total 1980 skew    0 clock   37.5KHz
        v: height  720 start  725 end  730 total  750           clock   50.0Hz
  1280x720 (0x42)   74.2MHz +HSync +VSync *current
        h: width  1280 start 1390 end 1430 total 1650 skew    0 clock   45.0KHz
        v: height  720 start  725 end  730 total  750           clock   60.0Hz
  720x576 (0x43)   27.0MHz -HSync -VSync
        h: width   720 start  732 end  796 total  864 skew    0 clock   31.2KHz
        v: height  576 start  581 end  586 total  625           clock   50.0Hz
  720x480 (0x44)   27.0MHz -HSync -VSync
        h: width   720 start  736 end  798 total  858 skew    0 clock   31.5KHz
        v: height  480 start  489 end  495 total  525           clock   59.9Hz
  640x480 (0x45)   25.2MHz -HSync -VSync
        h: width   640 start  656 end  752 total  800 skew    0 clock   31.5KHz
        v: height  480 start  490 end  492 total  525           clock   59.9Hz

openembedded.md

Layers

The openembedded build system is organized in layers.

See ahow to create a new layer.

The ihnerit keyword is used to subclass a .bbclass.

• From BitBake to Hello World tutorial

Packages

Add package to image

reversing.md

$ git clone https://github.com/devttys0/binwalk.git && cd binwalk
$ python setup.py install
# sudo ./deps.sh
# apt-get install p7zip-full zlib1g-dev:amd64 liblzma-dev:amd64 liblzo2-dev:amd64
$ binwalk -eM ./DVRF_v01.bin

• http://b1ack0wl.com/projects/2016/01/20/Getting-Started-With-DVRF/

u-boot.md

$ git clone git://git.denx.de/u-boot.git
$ cd u-boot
$ make versatileqemu_defconfig #QEMU
$ make ARCH=arm
$ qemu-system-arm -M versatilepb -kernel u-boot

Now pressing Ctrl-3 you have access to the u-boot console (otherwise use -serial /dev/stdio to have u-boot console in the terminal).

If you want to edit the configuration of the board edit the correct file in the directory include/configs/.