diff --git a/docs/companion_contact_cache.md b/docs/companion_contact_cache.md
index b1343a50..f5015f17 100644
--- a/docs/companion_contact_cache.md
+++ b/docs/companion_contact_cache.md
@@ -140,6 +140,14 @@ OUTPUT_DIR=.releases/contact-cache-v3 bash build.sh build-firmware \
 The firmware RAM guard remains enabled. A successful linked budget is distinct
 from live free heap and physical Bluetooth/LoRa qualification on each board.
 
+The smaller NimBLE applications let the CT62, XIAO C3 and Generic ESP-NOW
+trials use two 1.5 MiB WiFi OTA slots on 4 MiB flash. Their 896 KiB SPIFFS and
+coredump stay at the same addresses as the ordinary `huge_app.csv` Full
+layout. Install the trial's merged image over USB first to install its
+partition table. Subsequent WiFi updates must fit the new slots. An
+application-only update from the ordinary single-slot Full layout cannot
+change that layout or enable WiFi OTA.
+
 ## Regression checks
 
 ```sh
diff --git a/platformio.nimble.ini b/platformio.nimble.ini
index c5a1fee3..ad922702 100644
--- a/platformio.nimble.ini
+++ b/platformio.nimble.ini
@@ -77,6 +77,7 @@ lib_ignore = ${companion_nimble_trial.lib_ignore}
 
 [env:Heltec_ct62_ram_trial_companion_radio_full_nimble]
 extends = env:Heltec_ct62_companion_radio_ble
+board_build.full_partitions = variants/dual_ota_1536k.csv
 build_flags =
   ${env:Heltec_ct62_companion_radio_ble.build_flags}
   ${companion_nimble_ram_trial.build_flags}
@@ -87,6 +88,7 @@ lib_ignore = ${companion_nimble_trial.lib_ignore}
 
 [env:Xiao_C3_ram_trial_companion_radio_full_nimble]
 extends = env:Xiao_C3_companion_radio_wifi
+board_build.full_partitions = variants/dual_ota_1536k.csv
 build_flags =
   ${env:Xiao_C3_companion_radio_wifi.build_flags}
   ${companion_nimble_ram_trial.build_flags}
@@ -97,6 +99,7 @@ lib_ignore = ${companion_nimble_trial.lib_ignore}
 
 [env:Generic_ESPNOW_ram_trial_companion_radio_full_nimble]
 extends = env:Generic_ESPNOW_comp_radio_usb
+board_build.full_partitions = variants/dual_ota_1536k.csv
 build_flags =
   ${env:Generic_ESPNOW_comp_radio_usb.build_flags}
   ${companion_nimble_ram_trial.build_flags}
diff --git a/scripts/esp32_full_partition.py b/scripts/esp32_full_partition.py
index 153976d4..9a36f683 100644
--- a/scripts/esp32_full_partition.py
+++ b/scripts/esp32_full_partition.py
@@ -12,6 +12,10 @@ PRESERVED_FULL_PARTITION_TABLES = {
     "variants/sensecap_indicator-espnow/dual_ota_6400k_preserve_spiffs.csv",
 }
 
+# Explicitly selected by the smaller NimBLE capacity trials. The normal
+# 4 MiB Full Companion still needs huge_app.csv for its larger application.
+OPT_IN_FULL_PARTITION_TABLES = {"variants/dual_ota_1536k.csv"}
+
 
 def parse_flash_size(value):
     text = str(value).strip().upper()
@@ -39,10 +43,14 @@ if os.environ.get("MESHCORE_ESP32_FULL_BUILD") == "1":
     flash_size = parse_flash_size(board.get("upload.flash_size", "4MB"))
     requested_partitions = os.environ.get(
         "MESHCORE_ESP32_FULL_PARTITION_TABLE", ""
-    ).strip()
+    ).strip() or str(board.get("build.full_partitions", "")).strip()
     required_partitions = preserved_full_partition_table(
         requested_partitions
     )
+    if requested_partitions in OPT_IN_FULL_PARTITION_TABLES:
+        if flash_size < 4 * 1024 * 1024:
+            raise ValueError("Full dual-OTA trial requires at least 4 MiB flash")
+        required_partitions = requested_partitions
     if requested_partitions and not required_partitions:
         raise ValueError(
             "unsupported required Full partition table: "
diff --git a/test/test_esp32_full_partition.py b/test/test_esp32_full_partition.py
index c10ffc28..423c94d2 100644
--- a/test/test_esp32_full_partition.py
+++ b/test/test_esp32_full_partition.py
@@ -170,6 +170,32 @@ class Esp32FullPartitionTest(unittest.TestCase):
         )
         self.assertEqual(board.values["build.partitions"], "huge_app.csv")
 
+    def test_explicit_small_full_trial_uses_dual_ota_with_large_spiffs(self):
+        table = "variants/dual_ota_1536k.csv"
+        board, _output = apply_policy(
+            {
+                "upload.flash_size": "4MB",
+                "build.mcu": "esp32c3",
+                "build.partitions": "huge_app.csv",
+                "build.full_partitions": table,
+            }
+        )
+        self.assertEqual(board.values["build.partitions"], table)
+        # Retain the huge_app SPIFFS/coredump placement and enough storage for
+        # two complete 350-contact snapshots, rather than the 64 KiB table.
+        partitions = (ROOT / table).read_text()
+        self.assertIn("spiffs,   data, spiffs,  0x310000,0xE0000", partitions)
+        self.assertIn("app1,     app,  ota_1,   0x190000,0x180000", partitions)
+
+    def test_explicit_small_full_trial_rejects_insufficient_flash(self):
+        with self.assertRaisesRegex(ValueError, "at least 4 MiB"):
+            apply_policy(
+                {
+                    "upload.flash_size": "2MB",
+                    "build.full_partitions": "variants/dual_ota_1536k.csv",
+                }
+            )
+
     def test_tbeam_1w_factory_layout_keeps_precedence(self):
         board, _output = apply_policy(
             {