diff --git a/Makefile b/Makefile
index 6bf1218..70afe3a 100644
--- a/Makefile
+++ b/Makefile
@@ -40,15 +40,24 @@ endif
 ifeq ($(RBOOT_RTC_ENABLED),1)
 	CFLAGS += -DBOOT_RTC_ENABLED
 endif
+ifeq ($(RBOOT_CONFIG_CUSTOM),1)
+	CFLAGS += -DBOOT_CONFIG_CUSTOM
+endif
 ifeq ($(RBOOT_CONFIG_CHKSUM),1)
 	CFLAGS += -DBOOT_CONFIG_CHKSUM
 endif
+ifeq ($(RBOOT_CONFIG_DEFAULTS),1)
+	CFLAGS += -DBOOT_CONFIG_DEFAULTS
+endif
 ifeq ($(RBOOT_GPIO_ENABLED),1)
 	CFLAGS += -DBOOT_GPIO_ENABLED
 endif
 ifneq ($(RBOOT_GPIO_NUMBER),)
 	CFLAGS += -DBOOT_GPIO_NUM=$(RBOOT_GPIO_NUMBER)
 endif
+ifeq ($(RBOOT_FALLBACK_ENABLED),1)
+	CFLAGS += -DBOOT_FALLBACK_ENABLED
+endif
 ifeq ($(RBOOT_IROM_CHKSUM),1)
 	CFLAGS += -DBOOT_IROM_CHKSUM
 endif
diff --git a/rboot.c b/rboot.c
index 0e95db5..87d7e1d 100644
--- a/rboot.c
+++ b/rboot.c
@@ -364,9 +364,13 @@ uint32 NOINLINE find_image(void) {
 		ets_memset(romconf, 0x00, sizeof(rboot_config));
 		romconf->magic = BOOT_CONFIG_MAGIC;
 		romconf->version = BOOT_CONFIG_VERSION;
+#ifndef BOOT_CONFIG_DEFAULTS
 		romconf->count = 2;
 		romconf->roms[0] = SECTOR_SIZE * (BOOT_CONFIG_SECTOR + 1);
 		romconf->roms[1] = (flashsize / 2) + (SECTOR_SIZE * (BOOT_CONFIG_SECTOR + 1));
+#else
+		set_defaults(romconf);
+#endif
 #ifdef BOOT_CONFIG_CHKSUM
 		romconf->chksum = calc_chksum((uint8*)romconf, (uint8*)&romconf->chksum);
 #endif
@@ -417,9 +421,18 @@ uint32 NOINLINE find_image(void) {
 	// check valid rom number
 	// gpio/temp boots will have already validated this
 	if (romconf->current_rom >= romconf->count) {
-		// if invalid rom selected try rom 0
-		ets_printf("Invalid rom selected, defaulting to 0.\r\n");
-		romToBoot = 0;
+		// if invalid rom selected try rom 0 or fallback if enabled
+#ifdef BOOT_FALLBACK_ENABLED
+		if (romconf->mode & MODE_FALLBACK) {
+			ets_printf("Invalid rom selected, defaulting to fallback.\r\n");
+			romToBoot = romconf->fallback_rom;
+		} else {
+#endif
+			ets_printf("Invalid rom selected, defaulting to 0.\r\n");
+			romToBoot = 0;
+#ifdef BOOT_FALLBACK_ENABLED
+		}
+#endif
 		romconf->current_rom = 0;
 		updateConfig = TRUE;
 	}
@@ -452,13 +465,36 @@ uint32 NOINLINE find_image(void) {
 		// for normal mode try each previous rom
 		// until we find a good one or run out
 		updateConfig = TRUE;
-		romToBoot--;
-		if (romToBoot < 0) romToBoot = romconf->count - 1;
-		if (romToBoot == romconf->current_rom) {
-			// tried them all and all are bad!
-			ets_printf("No good rom available.\r\n");
-			return 0;
+#ifdef BOOT_FALLBACK_ENABLED
+		if (romconf->mode & MODE_FALLBACK) {
+			if (romToBoot == romconf->fallback_rom) {
+				// tried them all incl. fallback and all are bad!
+				ets_printf("No good rom available.\r\n");
+				return 0;
+			}
+			romToBoot--;
+			if (romToBoot < 0) romToBoot = romconf->count - 1;
+			if (romToBoot == romconf->fallback_rom) {
+				// skip fallback rom in sequence (try as last resort only)
+				romToBoot--;
+				if (romToBoot < 0) romToBoot = romconf->count - 1;
+			}
+			if (romToBoot == romconf->current_rom) {
+				// tried them all and all are bad! -> now try fallback rom
+				romToBoot = romconf->fallback_rom;
+			}
+		} else {
+#endif
+			romToBoot--;
+			if (romToBoot < 0) romToBoot = romconf->count - 1;
+			if (romToBoot == romconf->current_rom) {
+				// tried them all and all are bad!
+				ets_printf("No good rom available.\r\n");
+				return 0;
+			}
+#ifdef BOOT_FALLBACK_ENABLED
 		}
+#endif
 		runAddr = check_image(romconf->roms[romToBoot]);
 	}
 
diff --git a/rboot.h b/rboot.h
index 3981c37..a4a1fec 100644
--- a/rboot.h
+++ b/rboot.h
@@ -34,6 +34,9 @@ extern "C" {
 // when BOOT_GPIO_ENABLED is enabled
 //#define BOOT_GPIO_NUM 16
 
+// uncomment to enable FALLBACK booting
+//#define BOOT_FALLBACK_ENABLED
+
 // uncomment to include .irom0.text section in the checksum
 // roms must be built with esptool2 using -iromchksum option
 //#define BOOT_IROM_CHKSUM
@@ -63,6 +66,7 @@ extern "C" {
 #define MODE_GPIO_ROM    0x01
 #define MODE_TEMP_ROM    0x02
 #define MODE_GPIO_ERASES_SDKCONFIG 0x04
+#define MODE_FALLBACK 0x08
 
 #define RBOOT_RTC_MAGIC 0x2334ae68
 #define RBOOT_RTC_READ 1
@@ -95,8 +99,12 @@ typedef struct {
 	uint8 current_rom;     ///< Currently selected ROM (will be used for next standard boot)
 	uint8 gpio_rom;        ///< ROM to use for GPIO boot (hardware switch) with mode set to MODE_GPIO_ROM
 	uint8 count;           ///< Quantity of ROMs available to boot
-	uint8 unused[2];       ///< Padding (not used)
+	uint8 fallback_rom;    ///< ROM to use for fallback with mode set to MODE_FALLBACK
+	uint8 unused[1];       ///< Padding (not used)
 	uint32 roms[MAX_ROMS]; ///< Flash addresses of each ROM
+#ifdef BOOT_CONFIG_CUSTOM
+	rboot_custom_config custom[MAX_ROMS];
+#endif
 #ifdef BOOT_CONFIG_CHKSUM
 	uint8 chksum;          ///< Checksum of this configuration structure (if BOOT_CONFIG_CHKSUM defined)
 #endif