diff --git a/user/cgipins.c b/user/cgipins.c
index d9e02f3..3159866 100644
--- a/user/cgipins.c
+++ b/user/cgipins.c
@@ -11,7 +11,7 @@ static char *map_names[] = {
   "esp-bridge", "jn-esp-v2", "esp-01(AVR)", "esp-01(ARM)", "esp-br-rev",
 };
 static char* map_func[] = { "reset", "isp", "conn_led", "ser_led" };
-static int8_t map_asn[][4] = {
+static int8_t map_asn[][5] = {
   { 12, 13,  0, 14 },  // esp-bridge
   { 12, 13,  0,  2 },  // jn-esp-v2
   {  0, -1,  2, -1 },  // esp-01(AVR)
@@ -92,7 +92,16 @@ int ICACHE_FLASH_ATTR cgiPinsSet(HttpdConnData *connData) {
   serledInit();
   statusInit();
 
-	jsonHeader(connData, 200);
+  if (configSave()) {
+    os_printf("New config saved\n");
+    httpdStartResponse(connData, 200);
+    httpdEndHeaders(connData);
+  } else {
+    os_printf("*** Failed to save config ***\n");
+    httpdStartResponse(connData, 500);
+    httpdEndHeaders(connData);
+    httpdSend(connData, "Failed to save config", -1);
+  }
 	return HTTPD_CGI_DONE;
 }
 
diff --git a/user/config.c b/user/config.c
index e6eec90..6163542 100644
--- a/user/config.c
+++ b/user/config.c
@@ -5,16 +5,84 @@
 #include "config.h"
 #include "espfs.h"
 
-FlashConfig flashConfig = {
+FlashConfig flashConfig;
+FlashConfig flashDefault = {
+  33, 0,
   MCU_RESET_PIN, MCU_ISP_PIN, LED_CONN_PIN, LED_SERIAL_PIN,
   115200,
   "esp-link\0                       ",
 };
 
+#define FLASH_ADDR   (0x3E000)
+#define FLASH_SECT   (4096)
+static int flash_pri; // primary flash sector (0 or 1, or -1 for error)
+
 bool ICACHE_FLASH_ATTR configSave(void) {
+  FlashConfig fc;
+  memcpy(&fc, &flashConfig, sizeof(FlashConfig));
+  uint32_t seq = fc.seq+1;
+  // erase secondary
+  uint32_t addr = FLASH_ADDR + (1-flash_pri)*FLASH_SECT;
+  if (spi_flash_erase_sector(addr>>12) != SPI_FLASH_RESULT_OK)
+    return false; // no harm done, give up
+  // write primary with incorrect seq
+  fc.seq = 0xffffffff;
+  fc.crc = 0x55aa55aa;
+  if (spi_flash_write(addr, (void *)&fc, sizeof(FlashConfig)) != SPI_FLASH_RESULT_OK)
+    return false; // no harm done, give up
+  // fill in correct seq
+  fc.seq = seq;
+  if (spi_flash_write(addr, (void *)&fc, sizeof(uint32_t)) != SPI_FLASH_RESULT_OK)
+    return false; // most likely failed, but no harm if successful
+  // now that we have safely written the new version, erase old primary
+  addr = FLASH_ADDR + flash_pri*FLASH_SECT;
+  flash_pri = 1-flash_pri;
+  if (spi_flash_erase_sector(addr>>12) != SPI_FLASH_RESULT_OK)
+    return true; // no back-up but we're OK
+  // write secondary
+  fc.seq = 0xffffffff;
+  if (spi_flash_write(addr, (void *)&fc, sizeof(FlashConfig)) != SPI_FLASH_RESULT_OK)
+    return true; // no back-up but we're OK
+  fc.seq = seq;
+  spi_flash_write(addr, (void *)&fc, sizeof(uint32_t));
   return true;
 }
 
+void ICACHE_FLASH_ATTR configWipe(void) {
+  spi_flash_erase_sector(FLASH_ADDR>>12);
+  spi_flash_erase_sector((FLASH_ADDR+FLASH_SECT)>>12);
+}
+
+static uint32_t ICACHE_FLASH_ATTR selectPrimary(FlashConfig *fc0, FlashConfig *fc1);
+
 bool ICACHE_FLASH_ATTR configRestore(void) {
+  FlashConfig fc0, fc1;
+  // read both flash sectors
+  if (spi_flash_read(FLASH_ADDR, (void *)&fc0, sizeof(FlashConfig)) != SPI_FLASH_RESULT_OK)
+    memset(&fc0, sizeof(FlashConfig), 0); // clear in case of error
+  if (spi_flash_read(FLASH_ADDR+FLASH_SECT, (void *)&fc1, sizeof(FlashConfig)) != SPI_FLASH_RESULT_OK)
+    memset(&fc1, sizeof(FlashConfig), 0); // clear in case of error
+  // figure out which one is good
+  flash_pri = selectPrimary(&fc0, &fc1);
+  // if neither is OK, we revert to defaults
+  if (flash_pri < 0) {
+    memcpy(&flashConfig, &flashDefault, sizeof(FlashConfig));
+    flash_pri = 0;
+    return false;
+  }
+  // copy good one into global var and return
+  memcpy(&flashConfig, flash_pri == 0 ? &fc0 : &fc1, sizeof(FlashConfig));
   return true;
 }
+
+static uint32_t ICACHE_FLASH_ATTR selectPrimary(FlashConfig *fc0, FlashConfig *fc1) {
+  bool fc0_crc_ok = fc0->crc == 0x55aa55aa && fc0->seq != 0xffffffff; // need real crc checksum...
+  bool fc1_crc_ok = fc1->crc == 0x55aa55aa && fc1->seq != 0xffffffff; // need real crc checksum...
+  if (fc0_crc_ok)
+    if (!fc1_crc_ok || fc0->seq >= fc1->seq)
+      return 0; // use first sector as primary
+    else
+      return 1; // second sector is newer
+  else
+    return fc1_crc_ok ? 1 : -1;
+}
diff --git a/user/config.h b/user/config.h
index 513f0c9..b4bed48 100644
--- a/user/config.h
+++ b/user/config.h
@@ -2,6 +2,8 @@
 #define CONFIG_H
 
 typedef struct {
+  uint32_t seq; // flash write sequence number
+  uint32_t crc; // FlashConfig crc
   int8_t  reset_pin, isp_pin, conn_led_pin, ser_led_pin;
   int32_t baud_rate;
   char    hostname[32];
@@ -10,5 +12,6 @@ extern FlashConfig flashConfig;
 
 bool configSave(void);
 bool configRestore(void);
+void configWipe(void);
 
 #endif
diff --git a/user/user_main.c b/user/user_main.c
index e6b40ec..b1b3f7c 100644
--- a/user/user_main.c
+++ b/user/user_main.c
@@ -24,6 +24,7 @@
 #include "status.h"
 #include "serled.h"
 #include "console.h"
+#include "config.h"
 #include "log.h"
 #define MCU_RESET 12
 #define MCU_ISP   13
@@ -121,6 +122,9 @@ void user_init(void) {
 # define VERS_STR_STR(V) #V
 # define VERS_STR(V) VERS_STR_STR(V)
 	os_printf("\n\nInitializing esp-link\n" VERS_STR(VERSION) "\n");
+	//configWipe();
+	if (configRestore()) os_printf("Flash config restored\n");
+	else os_printf("*** Flash config restore failed, using defaults ***\n");
 	// Status LEDs
 	statusInit();
 	serledInit();