Open Trickler Buildroot

This repo creates the Linux firmware images for the Open Trickler project.

Configuration

The following files and directories are the most relevant for Open Trickler:

configs/opentrickler_dev_defconfig
configs/opentrickler_prod_defconfig
package/python-opentrickler/
board/ammolytics/opentrickler/

Build commands

make opentrickler_dev_defconfig
make

The resulting firmware images will be in output/images/.

Syncing with upstream Buildroot

Always keep commits to the opentrickler-2022.05.x on top of the latest upstream 2022.05.x branch.

git checkout 2022.05.x
git pull
git checkout opentrickler-2022.05.x
git merge 2022.05.x
git push origin opentrickler-2022.05.x

Inspecting the image filesystem

First, use fdisk to list the partitions and block positions.

fdisk -l  output/images/sdcard.img

Example output

Disk output/images/sdcard.img: 596 MiB, 624951808 bytes, 1220609 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device                    Boot   Start     End Sectors  Size Id Type
output/images/sdcard.img1 *          1   65536   65536   32M  c W95 FAT32 (LBA)
output/images/sdcard.img2        65537 1089536 1024000  500M 83 Linux
output/images/sdcard.img3      1089537 1220608  131072   64M  c W95 FAT32 (LBA)

The math that determines the block offset needed to mount a parition

start * sector size = offset  # equation
1 * 512 = 512  # BOOT parition
65537 * 512 = 33554944  # Linux root partition
1089537 * 512 = 557842944  # CODE parition

Mounting the paritions (read-only)

sudo mkdir /mnt/ot-img/boot /mnt/ot-img/rootfs /mnt/ot-img/code
sudo mount -o loop,ro,sync,offset=512 output/images/sdcard.img /mnt/ot-img/boot
sudo mount -o loop,ro,offset=33554944 -t ext4 output/images/sdcard.img /mnt/ot-img/rootfs
sudo mount -o loop,ro,sync,offset=557842944 output/images/sdcard.img /mnt/ot-img/code

Unmount the paritions

sudo umount /mnt/ot-img/boot
sudo umount /mnt/ot-img/rootfs
sudo umount /mnt/ot-img/code