diff --git a/README.md b/README.md
index 06e523fa..fad37f69 100644
--- a/README.md
+++ b/README.md
@@ -1251,6 +1251,7 @@ function uflt12f(rawUflt12)
   - Adopt semantic versions completely [#726](https://github.com/mcci-catena/arduino-lmic/issues/726).
   - Implement JoinAccept CFList processing for US/AU [#739](https://github.com/mcci-catena/arduino-lmic/issues/739).
   - Correct JoinAccept CFList processing for AS923 [#740](https://github.com/mcci-catena/arduino-lmic/issues/740).
+  - Don't compile board config objects when we know for sure they'll not be used; compilers can't always tell [#736](https://github.com/mcci-catena/arduino-lmic/issues/736).
 
 - v3.3.0 is primarily a maintenance and roll-up release.
 
diff --git a/src/hal/getpinmap_catena4420.cpp b/src/hal/getpinmap_catena4420.cpp
index ae833b00..21431405 100644
--- a/src/hal/getpinmap_catena4420.cpp
+++ b/src/hal/getpinmap_catena4420.cpp
@@ -13,6 +13,10 @@ Copyright & License:
 
 */
 
+#if defined(ARDUINO_MCCI_CATENA_4420) || \
+    /* legacy names */ \
+    defined(ARDUINO_CATENA_4420)
+
 #include <arduino_lmic_hal_boards.h>
 #include <Arduino.h>
 
@@ -71,4 +75,6 @@ const HalPinmap_t *GetPinmap_Catena4420(void)
 	return &myPinmap;
 	}
 
-} // namespace Arduino_LMIC;
\ No newline at end of file
+} // namespace Arduino_LMIC
+
+#endif
diff --git a/src/hal/getpinmap_feather32u4lora.cpp b/src/hal/getpinmap_feather32u4lora.cpp
index c852eab8..715dfa5c 100644
--- a/src/hal/getpinmap_feather32u4lora.cpp
+++ b/src/hal/getpinmap_feather32u4lora.cpp
@@ -13,6 +13,8 @@ Copyright & License:
 
 */
 
+#if defined(ARDUINO_AVR_FEATHER32U4)
+
 #include <arduino_lmic_hal_boards.h>
 #include <Arduino.h>
 
@@ -77,3 +79,5 @@ const HalPinmap_t *GetPinmap_Feather32U4LoRa(void)
 	}
 
 }; // namespace Arduino_LMIC
+
+#endif // ARDUINO_AVR_FEATHER32U4
diff --git a/src/hal/getpinmap_featherm0lora.cpp b/src/hal/getpinmap_featherm0lora.cpp
index 7d221dcd..19751d39 100644
--- a/src/hal/getpinmap_featherm0lora.cpp
+++ b/src/hal/getpinmap_featherm0lora.cpp
@@ -13,6 +13,11 @@ Copyright & License:
 
 */
 
+// The Adafruit FeatherM0 and FeatherM0 Express BSPs are not consistent
+// as to how they declare themselves. Both are SAMDs. Detect either one.
+#if defined(ARDUINO_ARCH_SAMD)
+# if defined(ADAFRUIT_FEATHER_M0) || defined(ARDUINO_SAMD_FEATHER_M0)
+
 #include <arduino_lmic_hal_boards.h>
 #include <Arduino.h>
 
@@ -72,3 +77,6 @@ const HalPinmap_t *GetPinmap_FeatherM0LoRa(void)
 	}
 
 }; // namespace Arduino_LMIC
+
+# endif // defined(ADAFRUIT_FEATHER_M0) || defined(ARDUINO_SAMD_FEATHER_M0)
+#endif  // defined(ARDUINO_ARCH_SAMD)
diff --git a/src/hal/getpinmap_heltec_lora32.cpp b/src/hal/getpinmap_heltec_lora32.cpp
index 897907a5..43e0b37d 100644
--- a/src/hal/getpinmap_heltec_lora32.cpp
+++ b/src/hal/getpinmap_heltec_lora32.cpp
@@ -13,6 +13,8 @@ Copyright & License:
 
 */
 
+#if defined(ARDUINO_HELTEC_WIFI_LORA_32) || defined(ARDUINO_HELTEC_WIFI_LORA_32_V2) || defined(ARDUINO_HELTEC_WIRELESS_STICK)
+
 #include <arduino_lmic_hal_boards.h>
 #include <Arduino.h>
 
@@ -78,3 +80,5 @@ const HalPinmap_t *GetPinmap_heltec_lora32(void)
 }
 
 }; // namespace Arduino_LMIC
+
+#endif // defined(ARDUINO_HELTEC_WIFI_LORA_32) || defined(ARDUINO_HELTEC_WIFI_LORA_32_V2) || defined(ARDUINO_HELTEC_WIRELESS_STICK)
diff --git a/src/hal/getpinmap_ttgo_lora32_v1.cpp b/src/hal/getpinmap_ttgo_lora32_v1.cpp
index 71db3ebf..9beb370c 100644
--- a/src/hal/getpinmap_ttgo_lora32_v1.cpp
+++ b/src/hal/getpinmap_ttgo_lora32_v1.cpp
@@ -13,6 +13,8 @@ Copyright & License:
 
 */
 
+#if defined(ARDUINO_TTGO_LoRa32_V1)
+
 #include <arduino_lmic_hal_boards.h>
 #include <Arduino.h>
 
@@ -76,3 +78,5 @@ const HalPinmap_t * GetPinmap_ttgo_lora32_v1 (void)
 	}
 
 }; // namespace Arduino_LMIC
+
+#endif // ARDUINO_TTGO_LoRa32_V1