Printer.cfg for Anycubic Kobra 2 Plus/Pro/Max

Configs
42

You can downgrade using “Update via USB” process if you wanna try on lower firmware :wink:

43

I tried to downgrade, but it didn’t work. Now I tried again and installed 2.3.5. But I can’t get into the u-boot console.

44

Can anyone provide firmware dumps (any and all versions) for analyzing?

45

2.3.9 firmware if anybody needs it.

Change log:

  • Supports reading Gcode M600 commands for layer-specific material change.
  • Allow Z offset adjustment add 0.01mm .
  • Fix some bugs.
46

Just for the fun of it:

  • The firmware files are SWUpdate files
  • It can be extracted via cpio -idv < update.swu
  • The rootfs can be extracted via unsquashfs rootfs

Did not dig any deeper, but this might give you a start

47

You can also just open it with 7-zip

48

pretty sure this is 2.3.5 if anyone needs it. it was still on my udrive from when i updated.

49

Hi guys. Could someone just take a quick picture of where the UART port is located? Thanks.

50

Oh nvm I found it. It was right in the middle of the thing.

Edit: Just place the update folder on the root of USB and then place file inside that folder.

UART: 3 Volt 115200 baud rate.

51

Thanks for the firmware. Gonna take a look around!

@Barlow do you mind explaining how you replaced the shadow file? I have UART access now but I don’t know how to begin to replace the shadow password.

I’ll try to do it.

Did you just place a file on USB or did you do something to interrupt the boot process?

I can’t get past the boot delay thing. I tried holding but it won’t work. I can type but it’s just the regular login.

52

I sifted a bit through the rootfs of the firmware and there is a binary executable called app. Looking at the strings within this binary you can clearly see that it is actually Klipper.

It looks like that Anycubic has packed the entire Klipper installation into one single binary. From my PoV this means:

  • Anycubic is going to great lengths to obfuscate what they have modified in Klipper
  • Probably they have no intention to ever release a GPL compliant version
  • Any attempts to gain shell access to their board is kind of futile: Even if you do get it, you are faced with one single binary and reverse engineering this is likely close to impossible.
53

I tried to interrupt the boot process on firmware 1.15.0 2.1.2 2.3.5 2.3.6 2.3.9 but was unsuccessful.

54

Yeah I did that too. I tried looking for backdoors and stuff like that to give me root access but so far I haven’t found anything.

Honestly it would probably be better to keep it as it is or buy and open source printer that can be modified or buy like a ELEGOO Neptune 4 Max.

The best chance this printer has if we can replace the whole firmware on the printer with a custom one.

But so far this printer is guarded like a prison.

55

How did you find those firmwares? Do you mind sharing them?

56

Last time I check Elegoo did not do any better than Anycubic and as well is in breach of the GPL.
AFAIK they at least provide a regular Klipper install and not one that is binary packed.

57

Yeah but at least they have the webui fluidd thing.

58

Reading the U-Boot manual or some random website I can see that if we press/hold spam Ctrl-C and keep holding them and press the button on the baseboard as they mentioned as a reset switch which may be our entry point into the u-boot.

Link

EDIT: Tried it but it’s still the same. Will keep trying though.

EDIT 2: Tired to use autohotkey macro script but nothing so far.

59

The used Linux distribution seems to be OpenWRT, so maybe: [OpenWrt Wiki] Failsafe mode, factory reset, and recovery mode

60

Yeah the code for that might be found in: /etc/rc.button

EDIT: The button on the board seems to only reboot the device and nothing else.
I have tried to hold it but it doesn’t do anything until I release it and it just boots up normally.

Holding it for a long time won’t destroy any circuits right?

EDIT 2: I also tried to press the button a bunch of times like 5 and all of that. So far nothing.

It seems the button is something else than the openwrt button and seems to be a separate button that directly resets the CPU or something.

Not so sure but that’s what I think.

61

I found the firmware using Google.

Can anyone share 2.3.9 for k2pro?

To stop the boot process you need to hold down “s”