diff --git a/include/probe.h b/include/probe.h
index 34871f0..96df621 100644
--- a/include/probe.h
+++ b/include/probe.h
@@ -16,9 +16,6 @@ void probe_mode_switch(uint8_t mode);
 
 void probe_measure();
 
-void probe_set_thresh(uint8_t set);
-uint8_t probe_get_thresh();
-
 
 
 #endif /* _INC_PROBE_H */
\ No newline at end of file
diff --git a/src/flash.c b/src/flash.c
index 11faf82..373b3d4 100644
--- a/src/flash.c
+++ b/src/flash.c
@@ -174,6 +174,7 @@ __attribute__ ((long_call, section(".ramfunc"))) void flash_erase_page(uint32_t
 
     // enable EOPIE (per DS, EOP isn't set unless EOPIE is set)
     // and signal that we want to erase a page
+    FLASH->SR = FLASH_SR_EOP;
     FLASH->CR |= FLASH_CR_EOPIE | FLASH_CR_PER;
 
     // disable interrupts
@@ -186,15 +187,13 @@ __attribute__ ((long_call, section(".ramfunc"))) void flash_erase_page(uint32_t
     // ensure flash is not busy, then wait for end of programming
     while (FLASH->SR & FLASH_SR_BSY);
     while (!(FLASH->SR & FLASH_SR_EOP));
-
-    // re-enable interrupts
-    __set_PRIMASK(primask);
-
-    // clear EOP
     FLASH->SR |= FLASH_SR_EOP;
 
-    // and re-lock flash
+    // re-lock flash
     FLASH->CR = FLASH_CR_LOCK;
+    
+    // re-enable interrupts
+    __set_PRIMASK(primask);
 }
 
 /*
@@ -209,7 +208,7 @@ __attribute__ ((long_call, section(".ramfunc"))) void flash_write_page(uint32_t
     uint8_t i;
 
     uint32_t *src;
-    volatile uint32_t *dst;
+    uint32_t *dst;
 
     // ensure flash is not busy
     while (FLASH->SR & FLASH_SR_BSY);
@@ -221,6 +220,7 @@ __attribute__ ((long_call, section(".ramfunc"))) void flash_write_page(uint32_t
 
     // enable EOPIE (per DS, EOP isn't set unless EOPIE is set)
     // and signal that we want to write a page
+    FLASH->SR = FLASH_SR_EOP;
     FLASH->CR |= FLASH_CR_EOPIE | FLASH_CR_PG;
 
     // disable interrupts
@@ -229,28 +229,25 @@ __attribute__ ((long_call, section(".ramfunc"))) void flash_write_page(uint32_t
 
     // write data to flash
     src = data;
-    dst = (volatile uint32_t *)addr;
-    for (i = 0; i < (FLASH_PAGE_SIZE / 4); i++) {
-        // on the last page, enable the page write start bit to commit to flash
-        if (i == (FLASH_PAGE_SIZE / 4) - 1) {
-            FLASH->CR |= FLASH_CR_PGSTRT;
-        }
-        
+    dst = (uint32_t *)addr;
+    for (i = 0; i < (FLASH_PAGE_SIZE / 4) - 1; i++) {        
         *dst++ = *src++;
     }
 
+    // for the last word, enable the PGSTRT bit then write the word to commit to flash
+    FLASH->CR |= FLASH_CR_PGSTRT;
+    *dst = *src;
+
     // ensure flash is not busy, then wait for end of programming
     while (FLASH->SR & FLASH_SR_BSY);
     while (!(FLASH->SR & FLASH_SR_EOP));
-
-    // re-enable interrupts
-    __set_PRIMASK(primask);
-    
-    // clear EOP
     FLASH->SR |= FLASH_SR_EOP;
 
-    // and re-lock flash
+    // re-lock flash
     FLASH->CR = FLASH_CR_LOCK;
+    
+    // re-enable interrupts
+    __set_PRIMASK(primask);    
 }
 
 /*
@@ -262,7 +259,7 @@ void flash_commit_conf()
     uint32_t i;
     
     uint8_t flash_idx = 0;
-    uint8_t flash_full;
+    uint8_t flash_full = 0;
 
     struct UConf *fconf;
     uint32_t *f32, *u32;
@@ -280,7 +277,6 @@ void flash_commit_conf()
     // if all pages are occupied, erase the first page
     if (i == UCONF_COUNT) {
         flash_full = 1;
-        flash_erase_page(UCONF_FLASH_START);
     }
 
     // copy flash page from ROM to the write buffer,
@@ -310,6 +306,12 @@ void flash_commit_conf()
         *u32++ = *f32++;
     }
 
+    // erase this page
+    flash_erase_page(UCONF_FLASH_START + (UCONF_SIZE * flash_idx));
+
+    // commit to flash
+    flash_write_page(UCONF_FLASH_START + (UCONF_SIZE * flash_idx), write);
+
     // if flash was full, erase other pages
     if (flash_full) {
         for (i = (UCONF_FLASH_START + FLASH_PAGE_SIZE); i < FLASH_END; i += FLASH_PAGE_SIZE) {
diff --git a/src/probe.c b/src/probe.c
index d63b87f..862554a 100644
--- a/src/probe.c
+++ b/src/probe.c
@@ -16,56 +16,49 @@
 
 #include "adc.h"
 #include "led.h"
+#include "rgbprog.h"
 #include "userio.h"
 
-
-
-#define CONT_OPEN			1240
+#include "flash.h"
 
 
 
 // diode measurements at 3V3
-#define DIODE_OPEN			3860		// test unit measures ~4060 no D1, ~3960 with D1
-#define DIODE_SCHOTTKY		1960		// vishay 40V 1A SB140
-#define DIODE_STANDARD		2330		// fairchild 5V2 zener, forward biased
-#define DIODE_LED_BLUE		3190
-#define DIODE_LED_GRN		3040		// very dim
-#define DIODE_LED_RED		3020
-#define DIODE_SHORT			1900		// test unit measures ~1820
+#define DIODE_OPEN				3860		// test unit measures ~4060 no D1, ~3960 with D1
+#define DIODE_SCHOTTKY			1960		// vishay 40V 1A SB140
+#define DIODE_STANDARD			2330		// fairchild 5V2 zener, forward biased
+#define DIODE_LED_BLUE			3190
+#define DIODE_LED_GRN			3040		// very dim
+#define DIODE_LED_RED			3020
+#define DIODE_SHORT				1900		// test unit measures ~1820
 
 
-#define CONT_SHORTED		858			// worst case measured value of short
-#define CONT_47OHM			869			// measured value of 47ohm 1% resistor at room temp
-#define CONT_100OHM			886			// measured value of 100ohm 1% resistor at room temp
-#define CONT_EXTRA_COUNTS	8			// extra raw counts as a fudge factor, post-scaling
-#define CONT_LATCH_THRESH	15			// extra raw counts for latching indicator, post-scaling
+// continuity offsets from calibrated short value
+#define CONT_47OHM				16
+#define CONT_100OHM				34
 
-#define CONT_LATCH_TIMEOUT	4			// probe measurement passes to hold latched indicator
+#define CONT_EXTRA_COUNTS		3		// extra raw counts as a fudge factor
+
+#define CONT_CAL_THRESHOLD		890		// typical short is ~845-860 region
+
+#define CONT_LATCH_THRESHOLD	5		// extra raw counts for latching indicator
+#define CONT_LATCH_TIMEOUT		4		// probe measurement passes to hold latched indicator
 
 
 
 static uint16_t vref;
 
-static uint16_t cont_thresh_set = 0;
-static const uint16_t cont_thresh[] = {
+static uint8_t cont_cal_timer;
+static uint16_t cont_cal_low;
+static uint16_t cont_cal_avg;
+static const uint16_t cont_thresh_tbl[] = {
 	CONT_100OHM, CONT_47OHM
 };
 
 static uint8_t latch = 0;
-static uint8_t buzzer = 0;
 
 
 
-void probe_set_thresh(uint8_t set)
-{
-	cont_thresh_set = set;
-}
-
-uint8_t probe_get_thresh()
-{
-	return cont_thresh_set;
-}
-
 static inline void probe_measure_cont()
 {
 	uint16_t probe, v_ext;
@@ -75,57 +68,105 @@ static inline void probe_measure_cont()
 	probe = adc_avg[ADC_PROBE];
 	v_ext = adc_avg[ADC_VREF_EXT];
 
-	// if the button has been pushed, toggle the buzzer
-	if (userio_get_btn() > 0) {
-		buzzer ^= 1;
-	}
+	// update vref
+	if (!vref) vref = v_ext;
+	vref += v_ext;
+	vref >>= 1;
 
 	// if the button has been held, change the threshold
 	if (userio_get_btn_held() == 60) {
 		userio_set_btn_override();
-		cont_thresh_set ^= 1;
+		conf.cont_sensitivity ^= 1;
 	}
 
-	// this LED will not set anything,
+	// if the button has _really_ been held, clear the calibration
+	if (userio_get_btn_held() == 600) {
+		conf.cont_shorted = 0;
+	}
+
+	// if there is no calibration, try to perform it
+	if (!conf.cont_shorted) {
+		// until this is performed, show error LEDs
+		rgbprog_error_flasher(5, 0, 0, 100);
+
+		// initialize
+		if (!cont_cal_timer) {
+			cont_cal_low = 0xfff;
+			cont_cal_avg = 0;
+		}
+
+		// if probe appears to be shorted, calibrate to lowest value read
+		if (adc_avg[ADC_PROBE] < CONT_CAL_THRESHOLD) {
+			// low value
+			if (adc_avg[ADC_PROBE] < cont_cal_low) {
+				cont_cal_low = adc_avg[ADC_PROBE];
+			}
+			// average value
+			if (!cont_cal_avg) {
+				cont_cal_avg = adc_avg[ADC_PROBE];
+			} else {
+				cont_cal_avg += adc_avg[ADC_PROBE];
+				cont_cal_avg >>= 1;
+			}
+			cont_cal_timer++;
+		} else {
+			cont_cal_timer = 0;
+		}
+
+		// after held long enough, commit
+		if (cont_cal_timer == 180) {
+			cont_cal_timer = 0;
+			conf.cont_shorted = (cont_cal_avg + cont_cal_low) >> 1;
+			flash_commit_conf();
+		}
+	}
+
+	// right LED remains unused while buzzer is being used,
 	// but zero it out anyway
 	led_setrgb(1, 0, 0, 0);
+
+	// if no calibration yet, bail here
+	if (!conf.cont_shorted) return;
+	
+	// if the button has been pushed, toggle buzzer on/off
+	if (userio_get_btn() > 0) {
+		conf.cont_buzzer ^= 1;
+	}
 	
 	if (vref) {
+		// note: we don't use VREF anymore...
+		// it's too noisy :/
+		
 		// probe level
-		x  = probe << 12;					// maximum possible level
-		x /= vref;							// normalize to 4096max
-		if (x > 4095) x = 4095;
+		x = probe - conf.cont_shorted;
+		if (x > 0xfff) x = 0;
 
 		// threshold level
-		c  = cont_thresh[cont_thresh_set] << 12;
-		c /= vref;
+		c  = cont_thresh_tbl[conf.cont_sensitivity];
 
-		// are we measuring a lower value?
+		// are we measuring a lower ohm value on the probes than our threshold?
 		if (x < (c + CONT_EXTRA_COUNTS)) {	// roughly 100ohm or lower
 			latch = CONT_LATCH_TIMEOUT;		// latch any continuity for a while
 		}
 
-		b = buzzer ? 100 : 0;
+		// blue led to indicate buzzer is enabled
+		b = conf.cont_buzzer ? 20 : 0;
 
 		if (latch) {
 			// hysteresis
-			if (x >= c + CONT_LATCH_THRESH) latch--;
+			if (x >= (c + CONT_LATCH_THRESHOLD)) latch--;
 
 			// indicate continuity
 			led_setrgb(0, 0, 250, b);
 			led_buzz(0);
-			if (buzzer) led_buzz(1);
+			if (conf.cont_buzzer) led_buzz(1);
 		} else {
 			// idle
-			g = cont_thresh_set ?  40 :  0;
+			g = conf.cont_sensitivity ? 40 : 0;
 			led_setrgb(0, 120, g, b);
 			led_buzz(0);
 		}
 	}
-
-	if (!vref) vref = v_ext;
-	vref += v_ext;
-	vref >>= 1;
 }
 
 static inline void probe_measure_diode()