Modified by ChatGPT for migration to microRecticulum_Firmware, not verified by me... yet, but I am preserving to document this stage.

docs/microreticulum_firmware_migration.md

@@ -29,6 +29,9 @@ so this repo consumes existing T-Beam SUPREME integration instead of duplicating
    - integration paths (from `microReticulum_Firmware`)
 6. After parity validation, remove or archive `external/microReticulum`.
 
+Step-2 inventory output:
+- `docs/microreticulum_firmware_step2_adoption_matrix.md`
+
 ## Validation Checklist
 - Build passes for all key exercises.
 - SD/RTC/GPS startup behavior remains stable.

docs/microreticulum_firmware_step2_adoption_matrix.md

@@ -0,0 +1,62 @@
+# Step 2 Adoption Matrix
+
+## Scope
+Repository: `microReticulumTbeam`  
+Submodule source: `external/microReticulum_Firmware`
+
+## What Step 2 Means
+Identify and wire the first low-risk points where this repo should consume existing board-integration logic from `microReticulum_Firmware`, instead of maintaining duplicate local assumptions.
+
+## High-Value Upstream Sources
+- `external/microReticulum_Firmware/Boards.h`
+  - T-Beam Supreme pin map and feature flags.
+  - Includes SD pins (`SD_CS=47`, `SD_CLK=36`, `SD_MISO=37`, `SD_MOSI=35`), PMU I2C pins (`I2C_SDA=42`, `I2C_SCL=41`), LoRa pins.
+- `external/microReticulum_Firmware/Power.h`
+  - AXP2101 setup sequence for T-Beam Supreme (`BOARD_TBEAM_S_V1`), including SD rail (BLDO1), ALDO rails, charging config.
+- `external/microReticulum_Firmware/platformio.ini`
+  - `env:ttgo-t-beam-supreme` build model and dependency pattern.
+
+## Local Targets And First Consumers
+1. `firmware/fieldtest_beacon/src/main.cpp`
+- Why first: this is the integration entry point, not just a smoke test.
+- Step-2 change made: SD CS now comes from `Boards.h` instead of hardcoded `10`.
+
+2. `exercises/04_SD_card/src/main.cpp`
+- Why second: duplicates PMU + SD pin assumptions already present upstream.
+- Planned consume-first item: PMU rail setup pattern from `Power.h`.
+
+3. `exercises/05_SD_Card_Watcher/src/main.cpp`
+- Why third: extends `04` and should share the same PMU/pin source strategy.
+- Planned consume-first item: same board/power source as `04`.
+
+4. `exercises/06_RTC_check/src/main.cpp`
+- Why fourth: depends on PMU + I2C pin assumptions that overlap upstream.
+- Planned consume-first item: board I2C pin source and PMU readiness sequence.
+
+## Current Wiring Done
+- Added submodule:
+  - `external/microReticulum_Firmware`
+- Wired one concrete consumer:
+  - `firmware/fieldtest_beacon/src/main.cpp` now includes `Boards.h` and uses `SD_CS`.
+  - `firmware/fieldtest_beacon/platformio.ini` now includes `external/microReticulum_Firmware` headers and sets `BOARD_MODEL=BOARD_TBEAM_S_V1`.
+- Added local adapter:
+  - `shared/boards/tbeam_supreme_adapter.h`
+  - Exposes board pins and PMU setup based on upstream T-Beam Supreme definitions.
+- Refactored exercises to consume adapter:
+  - `exercises/04_SD_card`
+  - `exercises/05_SD_Card_Watcher`
+  - `exercises/06_RTC_check`
+
+## Validation Status
+- `firmware/fieldtest_beacon` now builds after adding required deps:
+  - `ArduinoJson` 7.x
+  - `MsgPack`
+  - `Crypto` (provides `Ed25519.h` and `Curve25519.h`)
+- `exercises/04_SD_card` builds.
+- `exercises/05_SD_Card_Watcher` builds.
+- `exercises/06_RTC_check` builds.
+
+## Next Step Candidate
+Reduce macro redefinition warnings emitted by `Boards.h` in adapter consumers:
+- Option A: small local board-map header with only required constants copied from upstream board model.
+- Option B: upstream contribution to make board capability macros conditional/override-safe.