diff --git a/platformio.ini b/platformio.ini
index 87d26360..dc10360c 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -313,7 +313,9 @@ build_flags =
   -D RADIOLIB_EXCLUDE_SSTV=1
   -D ESP32_PLATFORM
   -D ENV_INCLUDE_GPS=1
-  -D ENV_INCLUDE_AHTX0=1
+  ; 0x38 is the FT6636 touch controller, not an AHT10/20. The Adafruit probe
+  ; mis-detects it as a sensor and can hang boot on its register 0xBA, so keep off.
+  -D ENV_INCLUDE_AHTX0=0
   -D ENV_INCLUDE_BME280=1
   -D ENV_INCLUDE_BMP280=1
   -D ENV_INCLUDE_SHTC3=1
@@ -323,7 +325,8 @@ build_flags =
   -D ENV_INCLUDE_INA219=1
   -D ENV_INCLUDE_INA226=1
   -D ENV_INCLUDE_INA260=1
-  -D ENV_INCLUDE_MLX90614=1
+  ; 0x5A is the keyboard module's AW9523 (left half), not an MLX90614.
+  -D ENV_INCLUDE_MLX90614=0
   -D ENV_INCLUDE_VL53L0X=1
   -D ENV_INCLUDE_BME680=1
   -D ENV_INCLUDE_BMP085=1
@@ -346,12 +349,18 @@ build_flags =
   -D MAX_LORA_TX_POWER=22
   -D SX126X_REGISTER_PATCH=1
   -D SX126X_DIO2_AS_RF_SWITCH=true
-  -D SX126X_DIO3_TCXO_VOLTAGE=1.8
+  ; Ra-01SH clocks the SX1262 from a 32 MHz crystal, not a TCXO, so DIO3 is not a
+  ; TCXO supply. Must be 0 explicitly: std_init() defaults to 1.6 V otherwise.
+  -D SX126X_DIO3_TCXO_VOLTAGE=0
   -D SX126X_CURRENT_LIMIT=140
   -D SX126X_RX_BOOSTED_GAIN=1
   -D PIN_GPS_RX=18
   -D PIN_GPS_TX=17
-  -D GPS_BAUD=9600
+  ; EnvironmentSensorManager reads GPS_BAUD_RATE, not GPS_BAUD.
+  -D GPS_BAUD_RATE=9600
+  ; ATGM336H cold-start can exceed the 1 s probe window. Without this the probe
+  ; gives up and start_gps() never runs, so GPS reads on but nothing is parsed.
+  -D ENV_SKIP_GPS_DETECT=1
   ; Keep the base rotation portrait; UITask applies the landscape transform.
   -D PIN_BOARD_SDA=2
   -D PIN_BOARD_SCL=1
diff --git a/src/main.cpp b/src/main.cpp
index a6e97a6a..d66d692b 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -710,8 +710,14 @@ void setup() {
   // hit the overflow) still get the big ring; default GPS-off keeps the stock 256 B. A user
   // who enables GPS mid-session picks it up on the next reboot (gps_enabled is persisted).
   {
+#if defined(ATTAKY_MESH_SERIES)
+    // This fixed stack always carries the GPS, so take the larger RX ring
+    // unconditionally; the default 256 B ring gives the slowest first fix.
+    Serial1.setRxBufferSize(4096);
+#else
     auto* np = the_mesh.getNodePrefs();
     if (np && np->gps_enabled) Serial1.setRxBufferSize(4096);
+#endif
   }
 #endif
   sensors.begin();