Raspberry Pi 5 Undervoltage (0x50000), Missing Hailo-8L NPU & USB Audio Failures

Standard phone chargers (9V/3A, 20V/3A) only negotiate 5V / 3A with Raspberry Pi 5. The PMIC then caps total USB port current to 600mA and drops below 4.63V when all 4 Cortex-A76 cores run NEON matrix math.

1. Use the official Raspberry Pi 27W USB-C Power Supply (which negotiates 5.1V / 5A).
2. Mount the official PWM Active Cooler so sustained 4-core inference stays around 60–65°C instead of hitting the 80°C thermal throttle ceiling.

# Verify PMIC negotiated 5A max current (expect 5000000 uA = 5A):
od -An -tx1 /proc/device-tree/chosen/power/max_current

# Verify zero throttling flags during active Ollama inference:
vcgencmd get_throttled

[BOUNDARY]Never set usb_max_current_enable=1 in config.txt on a weak 5V/3A charger—it risks brownout reboots and SD card corruption.

Either the external PCIe x1 controller is not enabled in /boot/firmware/config.txt, the bootloader EEPROM predates Hailo HAT+ support, or the 16-pin FPC ribbon cable is latched backward.

1. Add `dtparam=pciex1` and `dtparam=pciex1_gen=3` to `/boot/firmware/config.txt`.
2. Run `sudo rpi-eeprom-update -a` and `sudo apt install -y hailo-all`, then power off completely, reseat the FPC ribbon cable, and boot.

# 1. Enable PCIe x1 at Gen 3 speed
sudo sh -c 'printf "\ndtparam=pciex1\ndtparam=pciex1_gen=3\n" >> /boot/firmware/config.txt'

# 2. Update EEPROM firmware & install Hailo driver stack
sudo rpi-eeprom-update -a
sudo apt update && sudo apt install -y hailo-all
sudo reboot

[BOUNDARY]Remember: Hailo-8L NPU accelerates compiled .hef vision models (YOLO/ResNet), while Ollama GGUF LLMs run on the Cortex-A76 CPU.

Either your user lacks `/dev/snd/*` group permissions, or `hw:1,0` is rejecting 16kHz mono capture because the USB mic hardware only supports native 44.1kHz/48kHz stereo.

1. Add your user to the `audio` and `video` groups (`sudo usermod -aG audio,video $USER`) and re-login.
2. Use `plughw:1,0` instead of `hw:1,0` so ALSA automatically resamples 48kHz hardware audio down to 16kHz mono PCM for Whisper.cpp.

# 1. Grant device permissions
sudo usermod -aG audio,video $USER

# 2. Check USB microphone card & device index
arecord -l

# 3. Record 3s 16kHz mono WAV using plughw auto-resampler
arecord -D plughw:1,0 -f S16_LE -r 16000 -c 1 -d 3 /tmp/test.wav && aplay /tmp/test.wav

[BOUNDARY]In voice assistant loops, mute or pause mic capture while `aplay` is speaking so the assistant does not transcribe its own TTS voice.