Problem
pifinder_setup.sh:64-65 writes a single-channel PWM overlay:
grep -q "dtoverlay=pwm,pin=13,func=4" /boot/config.txt || \
echo "dtoverlay=pwm,pin=13,func=4" | sudo tee -a /boot/config.txt
That routes GPIO13 = PWM channel 1, which is the display backlight. The rev4 buzzer is on GPIO12 = PWM channel 0, which this overlay never routes.
Result: on a card provisioned by pifinder_setup.sh, the buzzer is silent — no startup, shutdown, keypress or low-battery tone — even though the hardware is fine and Settings → User Pref → Volume is set.
How it shows up
python -m PiFinder.bringup reports the buzzer as NOT ROUTED. That is the tool working correctly: it is a card provisioning fault, not a board fault. The risk is that a builder reads it as a bad solder joint and reworks a perfectly good part.
Suggested fix
Use the two-channel overlay so ch0 (buzzer) and ch1 (backlight) are both routed:
dtoverlay=pwm-2chan,pin=12,func=4,pin2=13,func2=4
Both pins are ALT0 (func=4) for their PWM function.
Needs care on upgrade: an existing card already carries the single-channel line, so the setup script should replace it rather than append a second, conflicting dtoverlay=.
Scope
Affects rev4 only (v3/v2.5 have no buzzer). Found while documenting the rev4 sound feature — the user docs currently describe tones that will not play on an affected card.
Problem
pifinder_setup.sh:64-65writes a single-channel PWM overlay:That routes GPIO13 = PWM channel 1, which is the display backlight. The rev4 buzzer is on GPIO12 = PWM channel 0, which this overlay never routes.
Result: on a card provisioned by
pifinder_setup.sh, the buzzer is silent — no startup, shutdown, keypress or low-battery tone — even though the hardware is fine andSettings → User Pref → Volumeis set.How it shows up
python -m PiFinder.bringupreports the buzzer asNOT ROUTED. That is the tool working correctly: it is a card provisioning fault, not a board fault. The risk is that a builder reads it as a bad solder joint and reworks a perfectly good part.Suggested fix
Use the two-channel overlay so ch0 (buzzer) and ch1 (backlight) are both routed:
Both pins are ALT0 (
func=4) for their PWM function.Needs care on upgrade: an existing card already carries the single-channel line, so the setup script should replace it rather than append a second, conflicting
dtoverlay=.Scope
Affects rev4 only (v3/v2.5 have no buzzer). Found while documenting the rev4 sound feature — the user docs currently describe tones that will not play on an affected card.