pedalboard.txt

The first partition of the card (or disk) is a small FAT partition named PEDALBOARD, readable from any computer. It holds pedalboard.txt, read at every boot:

# Audio interface: "auto" (the first USB interface or sound HAT), or a card
# name as listed in /proc/asound/cards, e.g. AudioBox or pisound
audio_device=auto

# Sample rate (Hz) and buffer (period frames x periods). 128 x 2 at 48 kHz
# adds about 5 ms each way; use 256 if you hear clicks.
sample_rate=48000
period=128
periods=2

# Screen rotation in degrees: 0, 90, 180 or 270
display_rotation=0

# Wi-Fi country, two letters (FR, DE, US...): opens the channels allowed there
wifi_country=

Key	Default
audio_device	auto	The first USB interface or sound HAT (HDMI is skipped), or a card name from /proc/asound/cards: AudioBox, pisound…
sample_rate	48000	In Hz. Keep 48 kHz for neural captures
period, periods	128, 2	The audio buffer. 128 × 2 at 48 kHz adds about 5 ms each way; 256 if you hear clicks
display_rotation	0	0, 90, 180 or 270
wifi_country	empty	Two letters (FR, US…)

Restart after editing. Keys are lowercase and values plain (letters, digits, _ . : , -): anything else is ignored and the default is used.

Other files on that partition

• authorized_keys: your SSH public keys, to log in over SSH.
• On the Pi, firmware settings of your own, such as a sound HAT’s overlay (dtoverlay=pisound), go in extra.txt on the SYSTEM partition in use (partition 2 on a new card). Updates keep it.