Maintain and emulate (Linux Mac Win) SD image with Raspbian ROS

Generate a new image

(see samepage, firmware section)

• dd bs=4M if=/dev/whereverSDcard of=/path/to/img/file.img; sync
• Can be easily compressed to about ~2Gb

Flash current image copy

• download current image copy from sailing robot google drive https://drive.google.com/open?id=0B0Wl35F24aqXUUdLUVBCVzlTZnc
• copy current image onto SD card: dd if=/path/to/img/file.img of=/dev/theSDcardDevice bs=4M; sync
• update launch scripts, firmware
• Alternatively use flash tool for RPi https://github.com/hypriot/flash

Shrink the image

If the SD card is smaller than the one used for the backup you can shrink the image before the copy, everything is explained here: http://softwarebakery.com/shrinking-images-on-linux .

If needed one can delete some files first (rosbags for example) by mounting the image locally.

sudo mount -o loop path/to/img/file.img somewhere/to/mount

QEMU emulator (Linux/Mac/Win)

(following https://github.com/dhruvvyas90/qemu-rpi-kernel/wiki/Emulating-Jessie-image-with-4.x.xx-kernel)

• Needs a .img file from the RPi and a ARM kernel, kernel-qemu-4.4.13-jessie in our case. Currently these files are in Tabarly: ~/kernel-qemu-4.4.13-jessie and ~/SDCardBack28March17.img. ~/rpi_image is an empty folder that can be used to mount the .img file to get the emulator ready.
• Comment out a few lines as explained in the article.
• Launch the emulator qemu-system-arm -kernel ~/kernel-qemu-4.4.13-jessie -cpu arm1176 -m 256 -M versatilepb -serial stdio -append "root=/dev/sda2 rootfstype=ext4 rw" -hda ~/SDCardBack28March17.img