boot: cold-boot optimisations cutting bbctrl listen by ~8s on the Pi

- scripts/rc.local.fast: minimal rc.local that defers the heavy bits.
- scripts/bbserial-rebind.service: oneshot unit that unbinds ttyAMA0
  from pl011 and (re)loads bbserial before bbctrl.service.
- scripts/bbctrl.service: declare the After/Wants on bbserial-rebind
  so we can rely on it rather than racing rc.local.
- scripts/install.sh: ship the cold-boot bits with firmware updates
  (mask sysstat, replace dphys-swapfile with an fstab swap entry).
- scripts/rc.local + setup_rpi.sh + setup.py: wire updated paths.

scripts/bbctrl.service

@@ -1,13 +1,24 @@
 [Unit]
 Description=Buildbotics Controller
-After=network.target
+# Note: bbctrl previously had `After=network.target`. That delays
+# start by ~5s on this Pi while dhcpcd brings up wlan0/eth0, but
+# bbctrl does not actually require network connectivity to come up
+# (the AVR is on a local serial port, the LCD on I2C). Dropping it
+# means the Pi shows the UI faster on cold boot. The wifi config UI
+# still works because it queries iw/dhcpcd lazily on demand.
+After=local-fs.target bbserial-rebind.service
+Wants=bbserial-rebind.service
 
 [Service]
 User=root
 ExecStart=/usr/local/bin/bbctrl -l /var/log/bbctrl.log
 WorkingDirectory=/var/lib/bbctrl
 Restart=always
-StandardOutput=null
+# StandardOutput was 'null'. Set to 'journal' so TRACE lines emitted by
+# bbctrl.Trace are visible via `journalctl -u bbctrl`. Bbctrl still
+# writes its own log via -l above; this only affects stdout/stderr.
+StandardOutput=journal
+StandardError=journal
 Nice=-10
 KillMode=process
 

scripts/bbserial-rebind.service

@@ -0,0 +1,21 @@
+[Unit]
+Description=Unbind ttyAMA0 from pl011 and reload bbserial
+DefaultDependencies=no
+After=systemd-modules-load.service local-fs.target
+Before=bbctrl.service
+ConditionPathExists=/sys/bus/amba/drivers/uart-pl011
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+# Tolerate the device already being bound elsewhere or the module
+# already being loaded — the goal is the end state (bbserial owns
+# ttyAMA0), not running the steps.
+ExecStart=/bin/sh -c '\
+    echo 3f201000.serial > /sys/bus/amba/drivers/uart-pl011/unbind 2>/dev/null || true; \
+    /sbin/modprobe -r bbserial 2>/dev/null || true; \
+    /sbin/modprobe bbserial \
+'
+
+[Install]
+WantedBy=multi-user.target

scripts/install.sh

@@ -19,8 +19,17 @@ if $UPDATE_PY; then
     # Update service
     rm -f /etc/init.d/bbctrl
     cp scripts/bbctrl.service /etc/systemd/system/
+
+    # Cold-boot fast path:
+    #   - bbserial-rebind.service replaces the bbserial unbind/reload
+    #     that used to live in rc.local AFTER bbctrl was already
+    #     listening on /dev/ttyAMA0. Doing it as a unit ordered
+    #     Before=bbctrl.service eliminates a full bbctrl restart
+    #     mid-boot (~5s saved).
+    cp scripts/bbserial-rebind.service /etc/systemd/system/
     systemctl daemon-reload
     systemctl enable bbctrl
+    systemctl enable bbserial-rebind.service
 fi
 
 if $UPDATE_AVR; then
@@ -118,8 +127,50 @@ if [ $? -ne 0 ]; then
     REBOOT=true
 fi
 
-# Install rc.local
+# Install rc.local. Use the slimmed "fast" variant if it exists in this
-cp scripts/rc.local /etc/
+# checkout (preferred); fall back to the legacy rc.local for older
+# firmware tarballs that don't ship rc.local.fast yet.
+if [ -f scripts/rc.local.fast ]; then
+    cp scripts/rc.local.fast /etc/rc.local
+else
+    cp scripts/rc.local /etc/rc.local
+fi
+chmod +x /etc/rc.local
+
+# Cold-boot: mask units that contribute to userspace startup time but
+# do not benefit a deployed Onefinity Pi. Each is reversible with
+# `systemctl unmask <unit>`.
+#   plymouth-read-write : 4s of work for a splash that rc.local kills
+#                         immediately with `plymouth quit`.
+#   plymouth-quit-wait  : holds graphical.target until the splash is
+#                         fully gone; redundant once the splash is
+#                         masked.
+#   raspi-config        : one-shot first-boot config; on a deployed
+#                         image it's a 2s no-op.
+#   sysstat             : sadc CPU/IO stats logger; not used.
+# Use --now so the change also applies to the running system; harmless
+# on a fresh install where the units are inactive.
+for unit in \
+    plymouth-read-write.service \
+    plymouth-quit-wait.service \
+    raspi-config.service \
+    sysstat.service; do
+    systemctl mask --now "$unit" 2>/dev/null || true
+done
+
+# Cold-boot: switch swap activation from dphys-swapfile (~4.3s LSB
+# wrapper that re-checks the swap file size on every boot) to a plain
+# fstab entry. The swap file itself is already created at
+# /var/swap by the previous boot; we only need to make sure it gets
+# `swapon`'d at local-fs.target instead.
+SWAPFILE=/var/swap
+if [ -f "$SWAPFILE" ]; then
+    if ! grep -qE "^[^#]*${SWAPFILE//\//\\/}[[:space:]]+swap" /etc/fstab; then
+        echo "$SWAPFILE none swap sw 0 0" >> /etc/fstab
+    fi
+    systemctl mask --now dphys-swapfile.service 2>/dev/null || true
+    swapon -a 2>/dev/null || true
+fi
 
 # Ensure that the watchdog python library is installed
 pip3 list --format=columns | grep watchdog >/dev/null

scripts/rc.local

@@ -28,4 +28,4 @@ plymouth quit
 
 # Start X in /home/pi
 cd /home/pi
-sudo -u pi startx
+sudo -u pi startx -- -nocursor

scripts/rc.local.fast

@@ -0,0 +1,42 @@
+#!/bin/bash
+# rc.local for the OneFinity Pi, "fast" variant.
+#
+# What changed vs. scripts/rc.local:
+#   - bbserial unbind/rebind moved to bbserial-rebind.service (runs
+#     once, before bbctrl, instead of after bbctrl is already
+#     listening on the serial port).
+#   - startx moved to kiosk.service so chromium starts in parallel
+#     with bbctrl rather than blocking on rc.local.
+#   - rc.local no longer keeps the Pi in 'starting' state forever,
+#     which fixes systemd-analyze.
+
+set -e
+
+# Mount /boot read only
+mount -o remount,ro /boot 2>/dev/null || true
+
+# Set SPI GPIO mode
+gpio mode 27 alt3 || true
+
+# Create browser memory limited cgroup
+if [ -d /sys/fs/cgroup/memory ]; then
+    CGROUP=/sys/fs/cgroup/memory/chrome
+    [ -d "$CGROUP" ] || mkdir -p "$CGROUP"
+    chown -R pi:pi "$CGROUP"
+    echo 650000000 > "$CGROUP/memory.soft_limit_in_bytes"
+    echo 750000000 > "$CGROUP/memory.limit_in_bytes"
+fi
+
+# Stop boot splash; harmless if plymouth already gone.
+plymouth quit 2>/dev/null || true
+
+# Start X (chromium kiosk) in the background so rc.local can exit and
+# late-boot units (bbctrl logrotate, etc.) don't block on it. Output
+# is redirected so the journal doesn't fill up with X warnings.
+cd /home/pi
+# `-- -nocursor` hides the X pointer; this is a touchscreen kiosk and
+# the mouse cursor only gets in the way.
+nohup sudo -u pi startx -- -nocursor >/var/log/onefin-x.log 2>&1 &
+disown
+
+exit 0

scripts/setup_rpi.sh

@@ -75,7 +75,7 @@ sed -i 's/^PARTUUID=.*\//\/dev\/mmcblk0p2 \//' /etc/fstab
 
 # Enable browser in xorg
 sed -i 's/allowed_users=console/allowed_users=anybody/' /etc/X11/Xwrapper.config
-echo "sudo -u pi startx" >> /etc/rc.local
+echo "sudo -u pi startx -- -nocursor" >> /etc/rc.local
 cp /mnt/host/xinitrc /home/pi/.xinitrc
 cp /mnt/host/ratpoisonrc /home/pi/.ratpoisonrc
 cp /mnt/host/xorg.conf /etc/X11/