BTT E3 RRF Support

ini/stm32f4.ini

@@ -173,6 +173,20 @@ build_unflags     = -DUSBCON -DUSBD_USE_CDC
 build_flags       = ${stm_flash_drive.build_flags}
   -DSTM32F407_5ZX -DVECT_TAB_OFFSET=0x8000
 
+#
+# BigTreeTech E3 RRF (STM32F407VGT6 ARM Cortex-M4)
+#
+[env:BIGTREE_E3_RRF]
+platform            = ${common_stm32.platform}
+extends             = common_stm32
+board               = genericSTM32F407VGT6
+board_build.variant = BIGTREE_E3_RRF
+build_flags         = ${common_stm32.build_flags}
+  -DSTM32F407_5VX -DVECT_TAB_OFFSET=0x8000
+  -DSERIAL_RX_BUFFER_SIZE=255 -DSERIAL_TX_BUFFER_SIZE=255
+extra_scripts       = ${common.extra_scripts}
+  pre:buildroot/share/PlatformIO/scripts/generic_create_variant.py
+
 #
 # Bigtreetech GTR V1.0 (STM32F407IGT6 ARM Cortex-M4)
 #