PiSound with Raspberry Pi 4

Regarding the Pi 4 reboot issue with Pisound, the issue seems to be a change of how the 3.3V supply on the GPIO header of Raspberry Pi 4 works - it now gets turned on with a 60ms delay, while 5V supply is available immediately, and during shutdown and reboot it gets turned off. 3.3V power supply on earlier Rasbperry Pi models was getting turned on nearly instantly.

There’s a temporary workaround available, consisting of 2 parts:

  1. Firmware EEPROM config update:

    1. Download the bootloader from https://www.raspberrypi.org/downloads/

    2. After extracting it, modify the config inside pieeprom.bin using this command:

      sed -i -e "s/WAKE_ON_GPIO=0/WAKE_ON_GPIO=1/" pieeprom.bin

      WAKE_ON_GPIO=1 will be the new default config value for RPi4, and eventually some update package will be released by Raspberry Pi developers.

    3. Move all of the extracted contents to an empty FAT-formatted SD card and insert it into your Raspberry Pi 4.

    4. Connect the power and wait for the green LED to flash quickly.

    5. Done, now you can power off and put in an SD card with OS.

  2. Kernel command line update (must be done everytime you flash the SD card):

    1. Add sdhci.debug_quirks2=4 to the end of /boot/cmdline.txt
    2. Reboot. Then the next time you reboot, this config should be take into account, RPi4 should not get stuck anymore.

The sdhci.debug_quirks2=4 disables ‘1.8V’ mode for SD card, so that makes UHS SD cards to be used at lower speeds, but this config also prevents power being cut off on the GPIO’s 3.3V supply, avoiding the reboot issue.

We are still working on some proper solution for the issue, but in the mean time, we recommend everyone using Raspberry Pi 4 with Pisound to apply the workaround steps. :slight_smile: