stuff

bootloader/CMakeLists.txt

@@ -0,0 +1,11 @@
+cmake_minimum_required(VERSION 3.16)
+
+# Minimal ESP-IDF project to build only the bootloader
+# You must have ESP-IDF installed and IDF_PATH exported.
+
+# Pin the target to ESP32-C6 to ensure correct bootloader build
+# (must be set before including project.cmake)
+set(IDF_TARGET "esp32c6")
+
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+project(custom_bootloader)

bootloader/README.md

@@ -0,0 +1,43 @@
+Custom ESP-IDF Bootloader (Rollback Enabled)
+
+This minimal project builds a custom ESP-IDF bootloader with rollback support enabled.
+You can flash it later alongside a Rust firmware using `espflash`.
+
+What this provides
+- A minimal ESP-IDF project (CMake) that can build just the bootloader.
+- Rollback support enabled via sdkconfig.defaults (CONFIG_BOOTLOADER_APP_ROLLBACK_ENABLE=y).
+- A sample OTA partition table (partitions.csv) suitable for OTA and rollback (otadata + two OTA slots).
+- A convenience script to build the bootloader for the desired target.
+
+Requirements
+- ESP-IDF installed and set up (IDF_PATH exported, Python env activated).
+- A selected target (esp32, esp32s3, esp32c3, etc.).
+
+Build
+1) Ensure ESP-IDF is set up:
+   source "$IDF_PATH/export.sh"
+
+2) Pick a target (examples):
+   idf.py set-target esp32
+   # or use the script:
+   ./build_bootloader.sh esp32
+
+3) Build only the bootloader:
+   idf.py bootloader
+   # or using the script (which also supports setting target):
+   ./build_bootloader.sh esp32
+
+Artifacts
+- build/bootloader/bootloader.bin
+
+Using with espflash (Rust)
+- For a no_std Rust firmware, you can pass this custom bootloader to espflash:
+  espflash flash --bootloader build/bootloader/bootloader.bin \
+                 --partition-table partitions.csv \
+                 <your-app-binary-or-elf>
+
+Notes
+- Rollback logic requires an OTA layout (otadata + at least two OTA app partitions). The provided partitions.csv is a starting point; adjust sizes/offsets to match your needs.
+- This project doesn’t build an application; it exists solely to produce a bootloader with the right configuration.
+- If you need different log verbosity or features, run `idf.py menuconfig` and then diff/port the changes back into sdkconfig.defaults.
+- Targets supported depend on your ESP-IDF version. Use `idf.py set-target <chip>` or `./build_bootloader.sh <chip>`.

bootloader/build_bootloader.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Build script for custom ESP-IDF bootloader with rollback enabled.
+# Requirements:
+#   - ESP-IDF installed
+#   - IDF_PATH exported
+#   - Python env prepared (the usual ESP-IDF setup)
+# Usage:
+#   ./build_bootloader.sh [esp32|esp32s3|esp32c3|esp32s2|esp32c2|esp32c6|esp32h2]
+#   If target is omitted, the last configured target will be used.
+
+TARGET=${1:-}
+
+if [[ -z "${IDF_PATH:-}" ]]; then
+  echo "ERROR: IDF_PATH is not set. Please install ESP-IDF and export the environment (source export.sh)." >&2
+  exit 1
+fi
+
+# shellcheck source=/dev/null
+source "$IDF_PATH/export.sh"
+
+if [[ -n "$TARGET" ]]; then
+  idf.py set-target "$TARGET"
+fi
+
+# Ensure sdkconfig.defaults is considered (ESP-IDF does this automatically).
+# Build only the bootloader.
+idf.py bootloader
+
+echo
+BOOTLOADER_BIN="build/bootloader/bootloader.bin"
+if [[ -f "$BOOTLOADER_BIN" ]]; then
+  echo "Bootloader built: $BOOTLOADER_BIN"
+  echo "You can use this with espflash via:"
+  echo "  espflash flash --bootloader $BOOTLOADER_BIN [--partition-table partitions.csv] <your-app-binary>"
+else
+  echo "ERROR: Bootloader binary not found. Check build logs above." >&2
+  exit 2
+fi
+cp build/bootloader/bootloader.bin ../rust/bootloader.bin

bootloader/main/CMakeLists.txt

@@ -0,0 +1 @@
+idf_component_register(SRCS "dummy.c" INCLUDE_DIRS ".")

bootloader/main/dummy.c

@@ -0,0 +1,4 @@
+// This file intentionally left almost empty.
+// ESP-IDF expects at least one component; the bootloader build does not use this.
+
+void __unused_dummy_symbol(void) {}

bootloader/partitions.csv

@@ -0,0 +1,6 @@
+nvs,      data, nvs,     ,        16k,
+otadata,  data, ota,     ,        8k,
+phy_init, data, phy,     ,        4k,
+ota_0,    app,  ota_0,   ,        3968k,
+ota_1,    app,  ota_1,   ,        3968k,
+storage,  data, littlefs,,        8M,

bootloader/sdkconfig.defaults

@@ -0,0 +1,17 @@
+# Target can be set with: idf.py set-target esp32|esp32s3|esp32c3|...
+# If not set via idf.py, ESP-IDF may default to a target; it's recommended to set it explicitly.
+
+# Explicitly pin target to ESP32-C6
+CONFIG_IDF_TARGET="esp32c6"
+CONFIG_IDF_TARGET_ESP32C6=y
+CONFIG_IDF_TARGET_ARCH_RISCV=y
+
+# Bootloader configuration
+CONFIG_BOOTLOADER_APP_ROLLBACK_ENABLE=y
+CONFIG_BOOTLOADER_LOG_LEVEL_INFO=y
+# Slightly faster boot by skipping GPIO checks unless you need that feature
+CONFIG_BOOTLOADER_SKIP_VALIDATE_IN_DEEP_SLEEP=y
+
+# Partition table config is not required to build bootloader, but shown for clarity when you build full app later
+# CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partitions.csv"
+# CONFIG_PARTITION_TABLE_FILENAME="partitions.csv"