Enabling the internal speaker on a CM5
A CM5 needs the RP1 audio remapped to GPIO 12/13 (dtoverlay=audremap,pins_12_13) and the amplifier enable pin driven high; current images already do both.
What it takes
- Config change
Difficulty 1 of 3 — easy.
Details
libbkmz worked it out in April 2025 when the CM5 was new: add dtoverlay=audremap-pi5,pins_12_13 to config.txt — kernel 6.12.17 or later, the version that brought RP1 audio out (raspberrypi/linux PR 6668) — then drive the amplifier enable (PA_EN, GPIO 580 on the CM5) high from rc.local with the sysfs export/direction/value commands, the CM5 counterpart of the CM4's GPIO 523.
Rex replied that his 6.12.y images have shipped working audio since release using dtoverlay=audremap,pins_12_13, so this is for people building their own image or debugging a silent speaker. Static at low battery is a separate problem with its own entry.
Links
Open at Forum threadRelated mods
Below roughly 15 % battery the CM5's speaker picks up boost-converter noise; beams' power_save=0 modprobe option or Rex's audio-disable package quiet it.
On a CM4 the speaker amplifier is switched on by the devterm-audio-patch package; if it goes quiet, reinstall the package or drive GPIO 523 high from rc.local.
A USB DAC sidesteps the mainboard's mono AW8110 amplifier and the core module's own codec or PWM output; one owner reports it resampling to 44.1 kHz/16-bit.
Koha's proposed ES9039Q2M DAC card on the expansion slot's I²S: 3.5 mm and 4.4 mm balanced headphone outputs, line-in, OPA1612 amps, about $75 — still a design.
Two layers of 0.5 mm thermal pad and a small aluminium heatsink on the CM5 SoC, held with thermal tape — about 10 °C cooler under load.
A CM4 socket protection adapter lifts the CM5 so a 0.5 mm pad reaches the back shell instead of the thick stock pad.