rkdeveloptool "Creating Comm Object failed!": Fix

Symptoms

rkdeveloptool ld lists the device, but db / wl / rd print "Creating Comm Object failed!"
Works with sudo but not as a normal user

Common causes

No udev rule for the Rockchip vendor ID (0x2207), so the device node is root-only
Another program (upgrade_tool, a VM passthrough, a second rkdeveloptool) has claimed the interface
Device dropped out of MaskROM between commands (unstable power / cable)

How to fix it

Add a udev rule and re-plug the board

echo 'SUBSYSTEM=="usb", ATTR{idVendor}=="2207", MODE="0666"' | sudo tee /etc/udev/rules.d/99-rockchip.rules
sudo udevadm control --reload-rules && sudo udevadm trigger

Make sure nothing else owns the device
Close upgrade_tool / RKDevTool, detach the USB device from any VM, and kill stray rkdeveloptool processes.
```
pgrep -a rkdeveloptool; pgrep -a upgrade_tool
```
Re-enter MaskROM and retry
Power-cycle into MaskROM, confirm with rkdeveloptool ld, then run the commands straight away.
```
rkdeveloptool ld
rkdeveloptool db rk3588_spl_loader_v1.xx.xxx.bin
```

Go deeper

FAQ

What does "Creating Comm Object failed!" mean?

rkdeveloptool can see the Rockchip USB device but cannot open it. It is almost always a USB permission problem on Linux, or another tool holding the device.

What causes "Creating Comm Object failed!"?

No udev rule for the Rockchip vendor ID (0x2207), so the device node is root-only; Another program (upgrade_tool, a VM passthrough, a second rkdeveloptool) has claimed the interface; Device dropped out of MaskROM between commands (unstable power / cable).

How do I fix "Creating Comm Object failed!"?

1. Add a udev rule and re-plug the board 2. Make sure nothing else owns the device: Close upgrade_tool / RKDevTool, detach the USB device from any VM, and kill stray rkdeveloptool processes. 3. Re-enter MaskROM and retry: Power-cycle into MaskROM, confirm with rkdeveloptool ld, then run the commands straight away.