must specify board target (e.g. waveshare_amoled_216), fixes 'flash all environments' bug.

flash.sh

@@ -1,16 +1,31 @@
 #!/bin/bash
-# Build and flash firmware to the SC01 Plus.
+# Build and flash Clawdmeter firmware on Linux.
+# Usage:
+#   ./flash.sh <board>                  # default port /dev/ttyACM0
+#   ./flash.sh <board> /dev/ttyACM1     # explicit USB serial port
+#
+# <board> is the PlatformIO env name, e.g. waveshare_amoled_216 or waveshare_amoled_18.
 set -e
 
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
-PORT="${1:-/dev/ttyACM0}"
+BOARD="$1"
+PORT="${2:-/dev/ttyACM0}"
 
-echo "=== Flashing Claude Usage Tracker ==="
-echo "Port: $PORT"
+if [ -z "$BOARD" ]; then
+    echo "Error: board env name is required."
+    echo "Usage: $0 <board> [port]"
+    echo "Available boards:"
+    grep -E '^\[env:' "$SCRIPT_DIR/firmware/platformio.ini" | sed 's/\[env:/  /;s/\]//'
+    exit 1
+fi
+
+echo "=== Flashing Clawdmeter ==="
+echo "Board: $BOARD"
+echo "Port:  $PORT"
 echo ""
 
 cd "$SCRIPT_DIR/firmware"
-~/.platformio/penv/bin/pio run -t upload --upload-port "$PORT"
+~/.platformio/penv/bin/pio run -e "$BOARD" -t upload --upload-port "$PORT"
 
 echo ""
 echo "=== Done! ==="