add ESP32 firmware

ESP32/README.md

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+# FindMy ESP32 firmware
+Straight copy from OpenHaystack with small changes to `flash_esp32.sh`, kept here for archival purposes.
+Please refer to https://github.com/seemoo-lab/openhaystack for more info, all credit goes there.
+
+## How to use:
+`esptool.py` from Espressiff needs to be installed, then just simply type
+```
+$ ./flash_esp32.sh <your base64 adv key>
+```

ESP32/flash_esp32.sh

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+#!/usr/bin/env bash
+
+cleanup() {
+    echo "cleanup ..."
+    rm "$KEYFILE"
+}
+
+# Directory of this script
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+
+# Defaults: Serial port to access the ESP32
+PORT=/dev/ttyUSB0
+
+# Defaults: Fast baud rate
+BAUDRATE=921600
+
+# Parameter parsing
+while [[ $# -gt 0 ]]; do
+    KEY="$1"
+    case "$KEY" in
+        -p|--port)
+            PORT="$2"
+            shift
+            shift
+        ;;
+        -s|--slow)
+            BAUDRATE=115200
+            shift
+        ;;
+        -h|--help)
+            echo "flash_esp32.sh - Flash the OpenHaystack firmware onto an ESP32 module"
+            echo ""
+            echo "Call: flash_esp32.sh [-p <port>] [-s] PUBKEY"
+            echo ""
+            echo "Required Arguments:"
+            echo "  PUBKEY"
+            echo "      The base64-encoded advertisement key"
+            echo ""
+            echo "Optional Arguments:"
+            echo "  -h, --help"
+            echo "      Show this message and exit."
+            echo "  -p, --port <port>"
+	    echo "      Specify the serial interface to which the device is connected. (default: $PORT)"
+            echo "  -s, --slow"
+            echo "      Use 115200 instead of 921600 baud when flashing."
+            echo "      Might be required for long/bad USB cables or slow USB-to-Serial converters."
+            exit 1
+        ;;
+        *)
+            if [[ -z "$PUBKEY" ]]; then
+                PUBKEY="$1"
+                shift
+            else
+                echo "Got unexpected parameter $1"
+                exit 1
+            fi
+        ;;
+    esac
+done
+
+# Sanity check: Pubkey exists
+if [[ -z "$PUBKEY" ]]; then
+    echo "Missing advertisement key, call with --help for usage"
+    exit 1
+fi
+
+# Sanity check: Port
+if [[ ! -e "$PORT" ]]; then
+    echo "$PORT does not exist, please specify a valid serial interface with the -p argument"
+    exit 1
+fi
+
+
+# Prepare the key
+KEYFILE="$SCRIPT_DIR/tmp.key"
+if [[ -f "$KEYFILE" ]]; then
+    echo "$KEYFILE already exists, stopping here not to override files..."
+    exit 1
+fi
+echo "$PUBKEY" | python3 -m base64 -d - > "$KEYFILE"
+if [[ $? != 0 ]]; then
+    echo "Could not parse the advertisment key. Please provide valid base64 input"
+    exit 1
+fi
+
+# Call esptool.py. Errors from here on are critical
+set -e
+trap cleanup INT TERM EXIT
+
+# Clear NVM
+esptool.py --after no_reset --port "$PORT" \
+    erase_region 0x9000 0x5000
+esptool.py --before no_reset --baud $BAUDRATE --port "$PORT" \
+    write_flash 0x1000  "$SCRIPT_DIR/build/bootloader/bootloader.bin" \
+                0x8000  "$SCRIPT_DIR/build/partition_table/partition-table.bin" \
+                0xe000  "$KEYFILE" \
+                0x10000 "$SCRIPT_DIR/build/openhaystack.bin"
+