Technician tool v0.5

Imported from the Google Drive folder 004-technician_tool/v0.5.

kota_tech/flash/plan.py

@@ -84,8 +84,11 @@ def build_plan(image: FirmwareImage, mode: Mode, port: str, workdir: Path,
                 hex(otadata.offset), str(ota_file), hex(ota0.offset), str(app_file)],
             est_s=20))
     else:
+        if image.kind != "merged":
+            raise ValueError("Full mode needs a complete image (bootloader + partition table + app); "
+                             "this file contains the app only - use App-only mode.")
         plan.steps.append(Step(
-            "write", "Write the complete factory image (erases pairing and OTA registration)",
+            "write", "Write the complete image (erases pairing and OTA registration)",
             _common(port, "hard_reset") + write_opts + ["0x0", str(image.path)],
             est_s=25))
     return plan