After a recent reboot of my 4B I noticed that my bluetooth connections had stopped working. I noticed that bluetoothctl reported no device, and further that sudo hciconfig hci0 up indicates Can't get device info: No such device. Based upon threads like this, I checked sudo systemctl status hciuart and don't see anything obviously wrong:

● hciuart.service - Configure Bluetooth Modems connected by UART
   Loaded: loaded (/lib/systemd/system/hciuart.service; enabled; vendor preset: enabled)
   Active: active (running) since Wed 2019-11-13 11:17:12 EST; 4h 22min ago
 Main PID: 674 (hciattach)
    Tasks: 1 (limit: 4915)
   Memory: 1.5M
   CGroup: /system.slice/hciuart.service
           └─674 /usr/bin/hciattach /dev/serial1 bcm43xx 3000000 flow -

Nov 13 11:17:04 spellbook-van systemd[1]: Starting Configure Bluetooth Modems connected by UART...
Nov 13 11:17:12 spellbook-van btuart[331]: bcm43xx_init
Nov 13 11:17:12 spellbook-van btuart[331]: Flash firmware /lib/firmware/brcm/BCM4345C0.hcd
Nov 13 11:17:12 spellbook-van btuart[331]: Set Controller UART speed to 3000000 bit/s
Nov 13 11:17:12 spellbook-van btuart[331]: Device setup complete
Nov 13 11:17:12 spellbook-van systemd[1]: Started Configure Bluetooth Modems connected by UART.

I've confirmed that /dev/serial is a symlink:

/dev/lrwxrwxrwx 1 root root 7 Nov 13 11:17 /dev/serial1 -> ttyAMA0.

I suspect I messed something up when attempting to configure a USB GPS device via gpsd on /dev/ttyACM0. My best guess is that I accidentally ran some command against /dev/ttyAMA0 instead of /dev/ttyACM0, but I can't think of what it may have been or what I might do to continue debugging. However, I'll note that sudo cat /dev/ttyAMA0 returns successfully but no output.

  • 1
    If you don't know how you broke it, neither do we. Just do what the rest of us would do - restore from your backup. – Milliways Nov 13 '19 at 22:44
  • 2
    @Milliways It's reasonable to ask for what steps should next be tried for debugging purposes. "Restoring from backups" is a nuclear option that teaches nothing. That's what we're here for, to learn, not to blindly press the buttons that make it work. – Zane Claes Nov 14 '19 at 15:19
  • There is no Raspberry Pi version 4B+, it's only 4B. – Ingo Nov 14 '19 at 18:00
  • 1
    @ZaneClaes If you wish to learn start again, record changes, make backups of all changed system files and you and we have some chance of answering. – Milliways Nov 15 '19 at 0:52

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