This covers the K1 Max with the older mainboard (CR4CU220812S11), I believe the new mainboard (CR4CU220812S12) allows downgrading firmware.
I ran into an issue after manually updating to the latest firmware, which stopped my printer from working. Creality's main software page does not mention that v2.3.5.34 is for printers upgraded with the CFS attachment (multi filament). Creality do not allow firmware downgrades on the older mainboards.
After much searching, and giving up on Creality Support, I found a working solution.
At this point I need to thank ednba on github for working out this solution.
You will be using CLI (Command Line Interface) with SSH. If you use Windows, search for CMD. Linux users shouldn't need instructions for this... But just in case.. Terminal on Debian based Linux.
To try and keep this simple each command is in BOLD, each line is a separate command, copy and paste the commands into the CLI window one at a time and press enter or return (after editing if required)
Ok, first, make sure you have your K1 Max connected to your network.
You will need a USB flash drive formatted in fat32, the firmware you want to install (download from Creality) needs to be copied to the root directory on the flash drive.
On my printer the login details are
user name: root
password: creality_2023
My printer is on IP.. 192.168.0.179, your's will be different.
1. Login to the printer...
ssh [email protected]
Change the IP address to match your printers connection. You can find this by loging into your router, check all connected IP addresses, then turn off your printer. The IP that disappears from the connected list is your printer.
Enter password at prompt
2. Clear modifications and enable Write access:
rm -rf /overlay/upper/*
mount -o remount,rw /
3. Create a "hacked" update script: (We copy the original to a temp folder and bypass the version check exit)
cp /etc/ota_bin/local_ota_update.sh /tmp/local_ota_update_forced.sh
sed -i 's/exit 1/echo "Ignoring lock..."/g' /tmp/local_ota_update_forced.sh
chmod +x /tmp/local_ota_update_forced.sh
4. Run the forced downgrade: (Make sure the .img filename matches the one on your USB drive)
/tmp/local_ota_update_forced.sh /tmp/udisk/sda1/ (Insert the file name for the firmware).img
So, for my firmware I ran this... /tmp/local_ota_update_forced.sh /tmp/udisk/sda1/CR4CU220812S11_ota_img_V1.3.3.36. img
5. Wait:
When I ran the downgrade it gave an error message, something like file not found. WAIT... It took about 20 seconds for the .img file to be located.
Once you see ota: stoped success, you can turn the printer off. On restart the downgraded firmware will be installed.
Again, thanks need to be given to ednba on github for finding the solution to force downgrade firmware.
I ran into an issue after manually updating to the latest firmware, which stopped my printer from working. Creality's main software page does not mention that v2.3.5.34 is for printers upgraded with the CFS attachment (multi filament). Creality do not allow firmware downgrades on the older mainboards.
After much searching, and giving up on Creality Support, I found a working solution.
At this point I need to thank ednba on github for working out this solution.
You will be using CLI (Command Line Interface) with SSH. If you use Windows, search for CMD. Linux users shouldn't need instructions for this... But just in case.. Terminal on Debian based Linux.
To try and keep this simple each command is in BOLD, each line is a separate command, copy and paste the commands into the CLI window one at a time and press enter or return (after editing if required)
Ok, first, make sure you have your K1 Max connected to your network.
You will need a USB flash drive formatted in fat32, the firmware you want to install (download from Creality) needs to be copied to the root directory on the flash drive.
On my printer the login details are
user name: root
password: creality_2023
My printer is on IP.. 192.168.0.179, your's will be different.
1. Login to the printer...
ssh [email protected]
Change the IP address to match your printers connection. You can find this by loging into your router, check all connected IP addresses, then turn off your printer. The IP that disappears from the connected list is your printer.
Enter password at prompt
2. Clear modifications and enable Write access:
rm -rf /overlay/upper/*
mount -o remount,rw /
3. Create a "hacked" update script: (We copy the original to a temp folder and bypass the version check exit)
cp /etc/ota_bin/local_ota_update.sh /tmp/local_ota_update_forced.sh
sed -i 's/exit 1/echo "Ignoring lock..."/g' /tmp/local_ota_update_forced.sh
chmod +x /tmp/local_ota_update_forced.sh
4. Run the forced downgrade: (Make sure the .img filename matches the one on your USB drive)
/tmp/local_ota_update_forced.sh /tmp/udisk/sda1/ (Insert the file name for the firmware).img
So, for my firmware I ran this... /tmp/local_ota_update_forced.sh /tmp/udisk/sda1/CR4CU220812S11_ota_img_V1.3.3.36. img
5. Wait:
When I ran the downgrade it gave an error message, something like file not found. WAIT... It took about 20 seconds for the .img file to be located.
Once you see ota: stoped success, you can turn the printer off. On restart the downgraded firmware will be installed.
Again, thanks need to be given to ednba on github for finding the solution to force downgrade firmware.
