USB Disk mode
If you soft-brick the CM3, you can attach it as a USB disk device and then change files to get it back into working order or read/write the entire disk image.
- remove the bottom panel, toggle the switch (seen through a PCB cutout) from RUN to DISK.
- plug the usb power directly into a computer.
first you'll need to get
rpiboot (or comparable) installed for your os.
for debian-based distros,
sudo apt-get install libusb-1.0-0-dev git clone --depth=1 https://github.com/raspberrypi/usbboot cd usbboot make
(for other linux distros, see the rpi docs.)
this assumes homebrew is installed.
brew install libusb git clone --depth=1 https://github.com/raspberrypi/usbboot cd usbboot make
once installed, run
rpiboot (note the
output should look something like:
Waiting for BCM2835/6/7 Sending bootcode.bin Successful read 4 bytes Waiting for BCM2835/6/7 Second stage boot server File read: start.elf Second stage boot server done
next, find the name of the norns disk.
a disk will show up in /dev/sd? (normally something like
diskutil list and note the name (norns is
3.9 GB so that's a good clue). the name will be something like
on mac os, it's important to unmount the disk before imaging (
diskutil unmountDisk /dev/disk<disk_name>). a successful command will look something like:
[~/norns] $ diskutil unmountDisk /dev/disk3 Unmount of all volumes on disk3 was successful
copy the image
to copy image to norns:
sudo dd if=image.img of=/dev/sdb bs=4MiB status=progress conv=sparse sync
sudo dd if=<my_img>.img of=/dev/r<disk_name> bs=4m conv=sparse sync
r prefix — this is important. it specifies the raw disk and your transfer will be far slower without it; for details, see this thread.)
if you want to see progress (it will take a while!), type
ctrl+t to send a
SIGINFO command which will cause
dd to dump status; for example, something like:
load: 2.24 cmd: dd 55210 uninterruptible 0.06u 7.48s 142+0 records in 141+0 records out 591396864 bytes transferred in 313.867907 secs (1884222 bytes/sec)
copy the image (from norns)
reverse of/if to copy from norns