diff --git a/fw/Makefile b/fw/Makefile
index 9ef0e6f..39fa3cf 100644
--- a/fw/Makefile
+++ b/fw/Makefile
@@ -30,7 +30,8 @@ OBJCOPY = $(AVR_PREFIX)objcopy
 #OBJDUMP = $(AVR_PREFIX)objdump
 SIZE = $(AVR_PREFIX)size
 
-OBJS = $(NAME).o accel.o dispatch.o hash.o image.o reset.o sample.o sweep.o \
+OBJS = $(NAME).o accel.o dispatch.o hash.o image.o param.o \
+       reset.o sample.o sweep.o \
        $(COMMON_OBJS)
 BOOT_OBJS = boot.o flash.o fw.o $(COMMON_OBJS)
 COMMON_OBJS = rf.o spi.o
diff --git a/fw/antorcha.c b/fw/antorcha.c
index 9e6c554..02b98da 100644
--- a/fw/antorcha.c
+++ b/fw/antorcha.c
@@ -15,6 +15,7 @@
 #include <stdint.h>
 
 #include "proto.h"
+#include "param.h"
 #include "rf.h"
 #include "dispatch.h"
 #include "sweep.h"
@@ -25,22 +26,6 @@
 #include "io.h"
 
 
-static struct sweep fwd_sweep = {
-	.pixel_ticks	= TP_FWD_PIX_DEFAULT,
-	.left		= PX_FWD_LEFT_DEFAULT,
-	.right		= PX_FWD_RIGHT_DEFAULT,
-	.forward 	= 1,
-};
-
-
-static struct sweep bwd_sweep = {
-	.pixel_ticks	= TP_BWD_PIX_DEFAULT,
-	.left		= PX_BWD_LEFT_DEFAULT,
-	.right		= PX_BWD_RIGHT_DEFAULT,
-	.forward 	= 0,
-};
-
-
 static volatile enum sync_state {
 	IDLE,	/* undecided */
 	BWD,	/* backward sweep */
@@ -53,11 +38,6 @@ static volatile uint32_t tR0, tR1, tL0, tL1;
 static volatile uint32_t tL, tR;
 static volatile bool wake = 0;
 
-static uint16_t xa_high = XA_HIGH_DEFAULT;
-static uint16_t xa_low = XA_LOW_DEFAULT;
-static uint32_t fwd_start = TP_FWD_START_DEFAULT;
-static uint32_t bwd_start = TP_BWD_START_DEFAULT;
-
 
 static void sync_sweep(bool x, uint16_t v)
 {
@@ -132,6 +112,7 @@ static const struct handler *protos[] = {
 	&image_handler,
 	&reset_handler,
 	&sample_handler,
+	&param_handler,
 	NULL
 };
 
diff --git a/fw/dispatch.h b/fw/dispatch.h
index 1085220..b8612f7 100644
--- a/fw/dispatch.h
+++ b/fw/dispatch.h
@@ -29,6 +29,7 @@ struct handler {
 extern struct handler image_handler;
 extern struct handler reset_handler;
 extern struct handler sample_handler;
+extern struct handler param_handler;
 
 
 bool dispatch(const uint8_t *buf, uint8_t len, const struct handler **protos);
diff --git a/fw/param.c b/fw/param.c
new file mode 100644
index 0000000..c02c24c
--- /dev/null
+++ b/fw/param.c
@@ -0,0 +1,105 @@
+/*
+ * fw/param.c - Parameter upload
+ *
+ * Written 2012 by Werner Almesberger
+ * Copyright 2012 Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <avr/pgmspace.h>
+
+#include "hash.h"
+#include "sweep.h"
+#include "image.h"
+#include "proto.h"
+#include "dispatch.h"
+
+
+struct sweep fwd_sweep = {
+	.pixel_ticks	= TP_FWD_PIX_DEFAULT,
+	.left		= PX_FWD_LEFT_DEFAULT,
+	.right		= PX_FWD_RIGHT_DEFAULT,
+	.forward	= 1,
+};
+
+
+struct sweep bwd_sweep = {
+	.pixel_ticks	= TP_BWD_PIX_DEFAULT,
+	.left		= PX_BWD_LEFT_DEFAULT,
+	.right		= PX_BWD_RIGHT_DEFAULT,
+	.forward	= 0,
+};
+
+uint16_t xa_high = XA_HIGH_DEFAULT;
+uint16_t xa_low = XA_LOW_DEFAULT;
+uint32_t fwd_start = TP_FWD_START_DEFAULT;
+uint32_t bwd_start = TP_BWD_START_DEFAULT;
+
+static struct params tmp;
+static bool failed;
+
+
+static void new_params(void)
+{
+	xa_high = tmp.xa_high;
+	xa_low = tmp.xa_low;
+
+	fwd_sweep.left = tmp.px_fwd_left;
+	fwd_sweep.right = tmp.px_fwd_right;
+	bwd_sweep.left = tmp.px_bwd_left;
+	bwd_sweep.right = tmp.px_bwd_right;
+
+	fwd_start = tmp.tp_fwd_start;
+	bwd_start = tmp.tp_bwd_start;
+	fwd_sweep.pixel_ticks = tmp.tp_fwd_pix;
+	bwd_sweep.pixel_ticks = tmp.tp_bwd_pix;
+}
+
+
+static bool param_more(uint8_t seq, uint8_t limit, const uint8_t *payload)
+{
+	switch (limit-seq) {
+	default:
+		hash_merge(payload, PAYLOAD);
+		break;
+	case 1:
+		hash_end();
+		failed = !hash_eq(payload, PAYLOAD, 0);
+		break;
+	case 0:
+		if (!hash_eq(payload, PAYLOAD, PAYLOAD))
+			failed = 1;
+		if (failed)
+			return 0;
+		new_params();
+		break;
+	}
+	return 1;
+}
+
+
+static bool param_first(uint8_t limit, const uint8_t *payload)
+{
+	hash_init();
+	hash_merge_progmem(image_secret, sizeof(image_secret));
+	hash_merge(payload, PAYLOAD);
+	memcpy(&tmp, payload, sizeof(tmp));
+	failed = 0;
+	return 1;
+}
+
+
+struct handler param_handler = {
+        .type   = PARAM,
+        .first  = param_first,
+        .more	= param_more,
+};
diff --git a/fw/param.h b/fw/param.h
new file mode 100644
index 0000000..8f53130
--- /dev/null
+++ b/fw/param.h
@@ -0,0 +1,30 @@
+/*
+ * fw/param.h - Parameter upload
+ *
+ * Written 2012 by Werner Almesberger
+ * Copyright 2012 Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+
+#ifndef PARAM_H
+#define	PARAM_H
+
+#include <stdint.h>
+
+#include "sweep.h"
+
+
+extern struct sweep fwd_sweep;
+extern struct sweep bwd_sweep;
+
+extern uint16_t xa_high;
+extern uint16_t xa_low;
+extern uint32_t fwd_start;
+extern uint32_t bwd_start;
+
+#endif /* !PARAM_H */