diff --git a/src/main/target/OMNIBUSF4/target.h b/src/main/target/OMNIBUSF4/target.h
index 2d517ac381..c93f11d0f6 100644
--- a/src/main/target/OMNIBUSF4/target.h
+++ b/src/main/target/OMNIBUSF4/target.h
@@ -56,8 +56,6 @@
 #define USBD_PRODUCT_STRING "OmnibusF4"
 #endif
 
-#define USE_CUSTOM_DEFAULTS
-
 #define LED0_PIN                PB5
 #define USE_BEEPER
 #define BEEPER_PIN              PB4
diff --git a/src/main/target/STM32F405/target.mk b/src/main/target/STM32F405/target.mk
index b870edfa15..d8da77d475 100644
--- a/src/main/target/STM32F405/target.mk
+++ b/src/main/target/STM32F405/target.mk
@@ -2,6 +2,8 @@ F405_TARGETS += $(TARGET)
 
 FEATURES       += SDCARD_SPI VCP ONBOARDFLASH
 
+# Use a full block (16 kB) of flash for custom defaults - with 1 MB flash we have more than we know how to use anyway
+
 CUSTOM_DEFAULTS_EXTENDED = yes
 
 TARGET_SRC = \
diff --git a/src/main/target/STM32F411/target.mk b/src/main/target/STM32F411/target.mk
index a6a0fd4457..927bba94a2 100644
--- a/src/main/target/STM32F411/target.mk
+++ b/src/main/target/STM32F411/target.mk
@@ -2,8 +2,6 @@ F411_TARGETS += $(TARGET)
 
 FEATURES       += SDCARD_SPI VCP ONBOARDFLASH
 
-CUSTOM_DEFAULTS_EXTENDED = yes
-
 TARGET_SRC = \
     $(addprefix drivers/accgyro/,$(notdir $(wildcard $(SRC_DIR)/drivers/accgyro/*.c))) \
     $(addprefix drivers/barometer/,$(notdir $(wildcard $(SRC_DIR)/drivers/barometer/*.c))) \
diff --git a/src/main/target/STM32F745/target.mk b/src/main/target/STM32F745/target.mk
index d6f9a6f228..7140abd1f7 100644
--- a/src/main/target/STM32F745/target.mk
+++ b/src/main/target/STM32F745/target.mk
@@ -2,8 +2,6 @@ F7X5XG_TARGETS += $(TARGET)
 
 FEATURES       += SDCARD_SPI VCP ONBOARDFLASH
 
-CUSTOM_DEFAULTS_EXTENDED = yes
-
 TARGET_SRC = \
     $(addprefix drivers/accgyro/,$(notdir $(wildcard $(SRC_DIR)/drivers/accgyro/*.c))) \
     $(addprefix drivers/barometer/,$(notdir $(wildcard $(SRC_DIR)/drivers/barometer/*.c))) \
diff --git a/src/main/target/STM32F7X2/target.mk b/src/main/target/STM32F7X2/target.mk
index 2ea79d2daf..bb6b2bf791 100644
--- a/src/main/target/STM32F7X2/target.mk
+++ b/src/main/target/STM32F7X2/target.mk
@@ -2,8 +2,6 @@ F7X2RE_TARGETS += $(TARGET)
 
 FEATURES       += SDCARD_SPI VCP ONBOARDFLASH
 
-CUSTOM_DEFAULTS_EXTENDED = yes
-
 TARGET_SRC = \
     $(addprefix drivers/accgyro/,$(notdir $(wildcard $(SRC_DIR)/drivers/accgyro/*.c))) \
     $(addprefix drivers/barometer/,$(notdir $(wildcard $(SRC_DIR)/drivers/barometer/*.c))) \
diff --git a/src/utils/make_config_hex.sh b/src/utils/make_config_hex.sh
index 1705d9885a..2cf35b3db2 100755
--- a/src/utils/make_config_hex.sh
+++ b/src/utils/make_config_hex.sh
@@ -1,9 +1,19 @@
 #!/bin/bash
 
+# Create hex file from custom defaults in order to flash separately
+#
+# This will only work if the target was built with 'CUSTOM_DEFAULTS_EXTENDED'
+#
+# Usage: make_config_hex <input file> <output directory> <config area start address>
+# Choose the config area start address from:
+#
+# STM32F405: 0x080FC000
+# STM32F411 / STM32F7X2: 0x0807C000
+# STM32F74X: 0x080F8000
+
 INPUT_FILE=$1
 DESTINATION_DIR=$2
-
-TARGET_ADDRESS=0x080FC000
+TARGET_ADDRESS=$3
 
 srec_cat ${INPUT_FILE} -binary -offset ${TARGET_ADDRESS} \
     -generate '(' -maximum-address ${INPUT_FILE} -binary -maximum-address ${INPUT_FILE} -binary -offset 1 ')' \