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FAQ

About USB booting, what is UASP?

  • Without UASP, a drive is mounted as a Mass Storage Device using Bulk Only Transport (or BOT), a protocol that was designed for transferring files way back in the USB 'Full speed' days, when the fastest speed you could get was a whopping 12 Mbps!
  • With USB 3.0, the BOT protocol cripples throughput. USB 3.0 has 5 Gbps of bandwidth, which is 400x more than USB 1.1. The old BOT protocol would transfer data in large chunks, and each chunk of data had to be delivered in order, without regard for buffering or multiple bits of data being able to transfer in parallel.
  • So a new protocol was created, called 'USB Attached SCSI Protocol', or 'UASP'

How to check if my drive is support UASP?

  • If you have a USB drive and don't want to take it apart and look up the specs of the controller chip, the only reliable way to tell if it's being mounted with UASP support or not is to plug it into your Pi, then run the command lsusb -t:
$ lsusb -t
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M
    |__ Port 1: Dev 2, If 0, Class=Mass Storage, Driver=uas, 5000M

This command lists all the USB devices in a tree, and for each of the hard drives, you should see a Driver listed. If it's uas (like in the above example), then your drive supports UASP and you'll get the best speed. If it's usb-storage, then it's using the older BOT protocol and you won't see the full potential.

Why does my fan not spin after the Pi has been idle for a while?

  • By default the DeskPi fan driver adjusts the speed according to the CPU temperature. When the temperature is below the fan rotation threshold (see the table in the README), the fan stops automatically. To pin the fan at a specific speed, run sudo deskpi-config and pick one of the static levels from the menu.

What are the credentials on the pre-installed Raspbian OS image?

  • Username: pi, password: raspberry. This is the standard Raspbian default; the DeskPi team does not change it when distributing the image.

Why is the pre-installed Raspbian OS image set up for China by default?

  • The pre-installed image is based on Raspbian Buster (2020-08-20), and during initialisation we have to set the Wi-Fi country before the Wi-Fi adapter can be enabled. The product is sold worldwide, so we cannot predict the buyer's country in advance — the default is therefore Shanghai, China. To change it, run sudo raspi-config and pick Localisation Options → WLAN Country.

The front panel USB port is unavailable.

  • That is almost always because dtoverlay=dwc2,dr_mode=host is missing from /boot/firmware/config.txt (or /boot/config.txt on legacy layouts). Add that line and reboot. The unified installer adds it for you automatically.

How do I change the hostname on the pre-installed Raspbian OS image?

  • Either run sudo raspi-config and pick System Options → S4 Hostname, or run sudo hostnamectl set-hostname YOURHOSTNAMEHERE from the command line.

How do I check whether my drive supports UASP?

  • Run lsusb -t | grep -i uas — drives listed with the uas driver support UASP and run at full speed; drives listed with usb-storage fall back to the older BOT protocol.

How do I install the DeskPi fan control driver after re-flashing the SD card?

  • Make sure your OS is on the supported list (see the README).
  • Make sure your Raspberry Pi can reach the internet.
  • Clone the repo and run the unified installer: 
    git clone https://github.com/DeskPi-Team/deskpi.git
cd ~/deskpi/installation
sudo ./install.sh
    The installer auto-detects your OS, prints what it is about to do, and asks for confirmation. To uninstall, run sudo ./uninstall.sh from the same directory.

Where is the list of supported OSes?

I double-press the front power button and the OS shuts down, but the 5 V rail stays on — the fan and the front USB LED never go off. What's wrong?

  • The DeskPi Pro daughter board cuts the 5 V rail only when it receives the literal byte sequence power_off over /dev/ttyUSB0 during the shutdown sequence. The OS-level systemctl poweroff only halts the CPU; on a Raspberry Pi 4 the firmware leaves 5 V on by default (POWER_OFF_ON_HALT=0 in the EEPROM config) and relies on the DeskPi Pro's MCU to do the actual cut.
  • A correct installation must therefore have two systemd units:
    1. deskpi.service — runs at boot, monitors the MCU for poweroff, calls systemctl poweroff when it sees it.
    2. deskpi-cut-off-power.service — Type=oneshot, WantedBy=poweroff.target, Before=halt.target shutdown.target poweroff.target, Conflicts=reboot.target. When systemd processes the power-off, this service starts first, runs /usr/bin/safeCutOffPower64 (which writes 9 bytes of power_off to the MCU), and exits cleanly in ~60 ms. The MCU then waits ~15 s and cuts the 5 V rail.
  • If only one of those two is present, you get exactly the symptoms above (OS halts, but the DeskPi Pro stays powered). The fix is to re-run the installer — the unified sudo ./install.sh is the easiest entry point; it auto-detects your OS and deploys both units. Verify with: 
    systemctl is-enabled  deskpi.service                  # enabled
systemctl is-enabled  deskpi-cut-off-power.service    # enabled
ls -l /usr/bin/safeCutOffPower64 /usr/bin/pwmFanControl64V2
  • You can also exercise the cut-off unit in isolation (this will trigger the MCU to cut 5 V ~15 s later, so only do it when you are ready to power-cycle the Pi): 
    sudo systemctl start deskpi-cut-off-power.service
    To see exactly which bytes were written, run it under strace first: 
    sudo strace -e openat,write /usr/bin/safeCutOffPower64
# expected last lines:
# openat(AT_FDCWD, "/dev/ttyUSB0", O_RDWR|O_NOCTTY) = 3
# write(3, "power_off", 9) = 9
# +++ exited with 0 +++
  • See CHANGELOG.md (2026-06-22 entry) for the full bug history.