This guide allows you to root a stock FLSun Speeder Pad without erasing anything. You only need a Phillips Screw driver, a plastic wedge tool, a USB to Serial USB Adapter (that supports 3v3) and 3 dupont female-female wires.
2024/03 - I noticed a typo in this guide on the setenv init lines which I corrected
2024/03 - Tested with clean FLSun v400 speeder-pad firmware at v1.4
Alternatively you can root the device by flashing a recovery image and overwriting the FLSun Klipper build: https://github.com/Guilouz/Klipper-Flsun-Speeder-Pad
1) Open the case Speeder Pad case: There are 2 Phillips screws and multiple snaps. Use a plastic thin wedge to unclip the snaps and separate the back cover from the device.
There is a 3 pin connector on the motherboard that has the labels RX,TX and GND
Connect a serial to USB adapter, set to 3v3
- RX->TX
- TX->RX
- GND-GND
2) Connect to the device with a serial console app like Putty or screen, the baud rate is 115200
To get a u-boot console you have to quickly press a key on your keyboard to interrupt bootup sequence, immediately after powering the device on with the 24vdc+ barrel connector coming from the printer
Once you are in the u-boot console:
=> setenv bootdelay 5
=> setenv init /bin/sh -m
=> saveenv
Saving Environment to SUNXI_FLASH... Writing to redundant env... OK
=> boot
After boot-up you should be presented with a logged in root session where you can add the pi user to the "sudo" group and change it's password:
/bin/sh: 0: can't access tty; job control turned off
# [ 7.159243]
[ 7.159243] insmod_device_driver
[ 7.159243]
# bash
bash: cannot set terminal process group (-1): Inappropriate ioctl for device
bash: no job control in this shell
root@(none):/# usermod -a -G sudo pi
root@(none):/# id pi
uid=1000(pi) gid=1000(pi) groups=1000(pi),4(adm),5(tty),20(dialout),27(sudo),44(video)
root@(none):/# passwd pi
Reboot and interrupt boot again
In u-boot console:
=> setenv init /sbin/init
=> saveenv
Saving Environment to SUNXI_FLASH... Writing to redundant env... OK
=> boot
Once the device boots, you can now connect to it via SSH with the pi / whatever_password_you_set
yes, i use putty on windows.
it could also be my serial cable, a usb-c to rj45 from delock.
(this cable works for example with pretty much all lan switches except Cisco. Cisco is special, yes, but still it could have something to do with the cable. I am not sure)