Submodule update error


Hey! Ive been having a problem getting the ardupilot submodule to update. when I type “git submodule update --init --recursive” I receive an error that states:

“fatal: read error: connection reset by peer
fatal: clone of git:// into submodule path ‘modules/Px4Firmware’ failed”

I was wondering if anyone has run into the same problem or if anyone can shed some light onto the situation.
Thank you!


Hi there Charles!

Hmmm that does sound weird. Just want to make sure you are 100% connected to the internet?

If so, maybe try this first:

git submodule init
then try
git submodule update --recursive

Also, out of curiosity, was your ardupilot repo installed with the “Copter-3.5.5” branch?


Awesome thank you! I’ll give that a try!
also yes I am connected to the internet and when I installed ardupilot i did use the “Copter-3.5.5” branch.
Thank you for helping me out, I’m still learning Linux .



But why are you downloading PX4 rather than ardupilot?

Should state

git clone -b Copter-3.5.5


No problem, let me know how it works or if we need to get back to the drawing board!


I believe there are some submodules of the PX4 repo that are used in the ArduPilot main repo, and are initialized with the git submodule update --init --recursive command.


Now I see it. I didn’t realize the course was relevant to PX4 installs.


Hey yall, thanks for helping. The problem was my wifi was blocking ssh. I switched to a VPN and was able to get it all to work.



been trying these commands… it or any variation doesn’t work


have tried these… mmmmm stuck!!!


Hi Dennis
Your are referring to a first time install?
I can try to help if you list exactly the code statements you are using.

How to Incorporate https:// with "git submodule update --init --recursive"

Hi, I just ran into that issue recently, it seems that starting 2022, github is updating their security. So they won’t allow unsecure or unauthenticated logins or downloads. See notes
I was able to perform the git submodule update --init --recursive (after) following their instructions which called to log into their secure git repositories.
The course calls out for git:// which is unsecure, maybe it can be updated in the future to point to the secure directory/repository.


@dronedojopadawan, could you elaborate in more detail what section to go to in the link you provided us to fix this issue? I’m new to Linux and I think I need change the URLs from the unsecured git:// to the secure https:// for the ChibiOS, benchmark, gtest, libcanard, mavlink, uavcan, etc. The 1st image shows my issue


Hello @charlestobin, did you switch to a VPN through your host computer or through Ubuntu? I am on a Mac and I want to try switching to a VPN because I am having the same “submodule update” issue.


The issue is a GitHub security update. you can no longer use the GIT:// protocol unauthenticated.

Just go into the ardupilot/.git/config file and change the submodule URLs from GIT:// to HTTPS:// and it will work.


Found a solution: (Fix: "git submodule update --init --recursive" ERROR: fatal: "unable to connect to"))

git config --global url.“https://”.insteadOf git://
git submodule update --init --recursive


This solution worked for me. Thank you!!


I also used that in combination with installing and using openvpn (free)