diff --git a/data.c b/data.c
index 0a43b6d..fdb0407 100644
--- a/data.c
+++ b/data.c
@@ -21,10 +21,10 @@ void data_free(struct data d)
 		free(d.val);
 }
 
-struct data data_grow_for(struct data d, int xlen)
+struct data data_grow_for(struct data d, unsigned int xlen)
 {
 	struct data nd;
-	int newsize;
+	unsigned int newsize;
 
 	if (xlen == 0)
 		return d;
diff --git a/dtc.h b/dtc.h
index a08f415..d3e82fb 100644
--- a/dtc.h
+++ b/dtc.h
@@ -105,13 +105,13 @@ extern const char *markername(enum markertype markertype);
 
 struct  marker {
 	enum markertype type;
-	int offset;
+	unsigned int offset;
 	char *ref;
 	struct marker *next;
 };
 
 struct data {
-	int len;
+	unsigned int len;
 	char *val;
 	struct marker *markers;
 };
@@ -129,7 +129,7 @@ size_t type_marker_length(struct marker *m);
 
 void data_free(struct data d);
 
-struct data data_grow_for(struct data d, int xlen);
+struct data data_grow_for(struct data d, unsigned int xlen);
 
 struct data data_copy_mem(const char *mem, int len);
 struct data data_copy_escape_string(const char *s, int len);
@@ -253,7 +253,7 @@ void append_to_property(struct node *node,
 const char *get_unitname(struct node *node);
 struct property *get_property(struct node *node, const char *propname);
 cell_t propval_cell(struct property *prop);
-cell_t propval_cell_n(struct property *prop, int n);
+cell_t propval_cell_n(struct property *prop, unsigned int n);
 struct property *get_property_by_label(struct node *tree, const char *label,
 				       struct node **node);
 struct marker *get_marker_label(struct node *tree, const char *label,
diff --git a/flattree.c b/flattree.c
index 07f10d2..4659afb 100644
--- a/flattree.c
+++ b/flattree.c
@@ -149,7 +149,7 @@ static void asm_emit_align(void *e, int a)
 static void asm_emit_data(void *e, struct data d)
 {
 	FILE *f = e;
-	int off = 0;
+	unsigned int off = 0;
 	struct marker *m = d.markers;
 
 	for_each_marker_of_type(m, LABEL)
@@ -219,7 +219,7 @@ static struct emitter asm_emitter = {
 
 static int stringtable_insert(struct data *d, const char *str)
 {
-	int i;
+	unsigned int i;
 
 	/* FIXME: do this more efficiently? */
 
@@ -345,7 +345,7 @@ static void make_fdt_header(struct fdt_header *fdt,
 void dt_to_blob(FILE *f, struct dt_info *dti, int version)
 {
 	struct version_info *vi = NULL;
-	int i;
+	unsigned int i;
 	struct data blob       = empty_data;
 	struct data reservebuf = empty_data;
 	struct data dtbuf      = empty_data;
@@ -446,7 +446,7 @@ static void dump_stringtable_asm(FILE *f, struct data strbuf)
 void dt_to_asm(FILE *f, struct dt_info *dti, int version)
 {
 	struct version_info *vi = NULL;
-	int i;
+	unsigned int i;
 	struct data strbuf = empty_data;
 	struct reserve_info *re;
 	const char *symprefix = "dt";
diff --git a/livetree.c b/livetree.c
index 032df58..7eacd02 100644
--- a/livetree.c
+++ b/livetree.c
@@ -438,7 +438,7 @@ cell_t propval_cell(struct property *prop)
 	return fdt32_to_cpu(*((fdt32_t *)prop->val.val));
 }
 
-cell_t propval_cell_n(struct property *prop, int n)
+cell_t propval_cell_n(struct property *prop, unsigned int n)
 {
 	assert(prop->val.len / sizeof(cell_t) >= n);
 	return fdt32_to_cpu(*((fdt32_t *)prop->val.val + n));
diff --git a/yamltree.c b/yamltree.c
index 4e93c12..e63d32f 100644
--- a/yamltree.c
+++ b/yamltree.c
@@ -29,11 +29,11 @@ char *yaml_error_name[] = {
 		    (emitter)->problem, __func__, __LINE__);		\
 })
 
-static void yaml_propval_int(yaml_emitter_t *emitter, struct marker *markers, char *data, int len, int width)
+static void yaml_propval_int(yaml_emitter_t *emitter, struct marker *markers, char *data, unsigned int len, int width)
 {
 	yaml_event_t event;
 	void *tag;
-	int off, start_offset = markers->offset;
+	unsigned int off, start_offset = markers->offset;
 
 	switch(width) {
 		case 1: tag = "!u8"; break;
@@ -112,7 +112,7 @@ static void yaml_propval_string(yaml_emitter_t *emitter, char *str, int len)
 static void yaml_propval(yaml_emitter_t *emitter, struct property *prop)
 {
 	yaml_event_t event;
-	int len = prop->val.len;
+	unsigned int len = prop->val.len;
 	struct marker *m = prop->val.markers;
 
 	/* Emit the property name */