• boot/: files for the FAT boot partition. extlinux/extlinux.conf boots BQ2 with cleave-init; fallback entries use busybox init or a rescue shell.
• rootfs/: files layered over the BQ2 seed, owned by root:
  • etc/cleave/init.json: mounts and services for cleave-init. These are mdev, syslog, a root shell on the ttyS2 console, DHCP on eth0, Wi-Fi with DHCP on wlan0, and NTP.
  • etc/mdev.conf: mdev loads the module for each device that appears, by its modalias.
  • etc/passwd, etc/group, etc/shadow: root and nobody. Logins are locked; the serial console is a root shell with no password, for bring-up with physical access.
  • etc/ld-musl-aarch64.path: adds /usr/lib/aarch64-bq2-linux-musl. The 0.4.0 seed's version leaves it out, so crystal and bq2 can't find libunwind.so.1.
  • usr/share/udhcpc/default.script: sets the address, route and DNS from DHCP.
  • usr/sbin/cleave-provision: Wi-Fi networks and hostname from the boot partition (see Wi-Fi).

Build the image with tools/build-beagley-ai-image.sh SEED BSP_DIR OUTPUT [LAYER...]. BSP_DIR holds tiboot3.bin, tispl.bin, u-boot.img, Image and dtb/ti/k3-am67a-beagley-ai.dtb. The script cross-compiles cleave-init against the seed's libraries and runs cleave-image.

Wi-Fi

The image has the CC33xx driver and firmware and wpa_supplicant, but no network to join: credentials never go into the image. At boot, /usr/sbin/cleave-provision (the provision service) writes /run/wpa_supplicant.conf from the FAT boot partition (/boot on the board):

• bb-imager-rs: flash with its customization set to cloud-init (--cloud-init on the command line). It writes cloud-init on the boot partition; the image takes its Wi-Fi network and hostname from it. Its user, SSH key, timezone and keyboard are not used yet. Its "sysconf" customization (sysconf.txt and an iwd .psk file) is not read.
• By hand: a wpa_supplicant.conf on the boot partition is used as it is, ahead of cloud-init, for example:

ctrl_interface=/run/wpa_supplicant
update_config=0

network={
	ssid="YOUR-SSID"
	psk="YOUR-PASSPHRASE"
}

The wifi service runs wpa_supplicant on wlan0 with it, and wifi-dhcp gets an address. Both are restarted until the interface and the file are there. Only WPA2-PSK is built in (wpa_supplicant's internal TLS has no SAE, so no WPA3). wpa_cli is there too.