Developing with Spresense SDK on WSL2

Sean Phillips

I came across this old forum post as I was investigating potential avenues for developing Spresense apps in WSL2. I followed along with the forum post and got to the point where I have the SDK setup in my WSL2 instance and a available /dev/ttyUSB0 device.

However, attempting to flash the bootloader on the device returns the following error:

~/*/spresense/sdk$ ./tools/flash.sh -l /home/*/spresense/firmware/spresense -c /dev/ttyUSB0
Cannot open port : /dev/ttyUSB0
Cannot configure port, something went wrong. Original message: OSError(22, 'Incorrect function.', None, 1)

I'm going to be spending some time looking into this issue and seeing if its possible to diagnose and resolve this error. However, I was curious if anyone had any success with developing on WSL2 and if they had any insights?

Sean Phillips

@Sean-Phillips
After a bit more digging I was able to figure out the issue (at least with running the flash.sh command to upload the bootloader). After applying the changes below, I was able to flash the bootloader

To give a tl;dr for folks needing a quick answer:

There is logic in the flash.sh script that will run flash_writer.exe if your environment is in WSL2. If the script utilizes this executable, there will be an error when attempting to write to /dev/ttyUSB0.

You can make the following adjustments to your flash.sh script for a quick fix:

# In File: /home/*/spresense/sdk/tools/flash.sh Comment out the following lines
@ lines 84-91
+ # if [ "${PLATFORM}" == "linux" ]; then
+ # 	if [ "$(uname -r | grep -i microsoft)" != "" ]; then
+ # 		# WSL/WSL2 is a linux but USB related SDK tools
+ # 		# should use windows binary.
+ # 		PLATFORM=windows
+ # 		EXEEXT=".exe"
+ # 	fi
+ # fi

This will prevent the flash.sh script from utilizing the flash_writer.exe file in the WSL2 environment. Rather, it will now just utilize the Linux binary version of the flash_writer.

I do know for a fact that running Windows binaries is possible in WSL2, but since the device is connected into WSL under /dev the flash_writer.exe binary cannot operate on it (Just a hunch).

CamilaSouza

Hi, @Sean-Phillips

Thanks for sharing your solution here!
It will be helpful for other developers in the future.

I will try this myself to validate the issue so the documentation can be updated.