diff --git a/util/cbfstool/cbfstool.c b/util/cbfstool/cbfstool.c
index 62edd4b7e6..8ad66c457c 100644
--- a/util/cbfstool/cbfstool.c
+++ b/util/cbfstool/cbfstool.c
@@ -38,7 +38,10 @@ struct command {
 	int (*function) (void);
 	// Whether to populate param.image_region before invoking function
 	bool accesses_region;
-	// Whether to write that region's contents back to image_file at the end
+	// This set to true means two things:
+	// - in case of a command operating on a region, the region's contents
+	//   will be written back to image_file at the end
+	// - write access to the file is required
 	bool modifies_region;
 };
 
@@ -1014,7 +1017,7 @@ static const struct command commands[] = {
 	{"print", "H:r:vh?", cbfs_print, true, false},
 	{"read", "r:f:vh?", cbfs_read, true, false},
 	{"remove", "H:r:n:vh?", cbfs_remove, true, true},
-	{"update-fit", "H:r:n:x:vh?", cbfs_update_fit, true, false},
+	{"update-fit", "H:r:n:x:vh?", cbfs_update_fit, true, true},
 	{"write", "r:f:udvh?", cbfs_write, true, true},
 };
 
@@ -1372,8 +1375,11 @@ int main(int argc, char **argv)
 				return 1;
 			}
 		} else {
+			bool write_access = commands[i].modifies_region;
+
 			param.image_file =
-				partitioned_file_reopen(image_name);
+				partitioned_file_reopen(image_name,
+							write_access);
 		}
 		if (!param.image_file)
 			return 1;
@@ -1429,7 +1435,6 @@ int main(int argc, char **argv)
 
 		if (commands[i].modifies_region) {
 			assert(param.image_file);
-			assert(commands[i].accesses_region);
 			for (unsigned region = 0; region < num_regions;
 								++region) {
 
diff --git a/util/cbfstool/partitioned_file.c b/util/cbfstool/partitioned_file.c
index f019d71fe4..7b4b0035f6 100644
--- a/util/cbfstool/partitioned_file.c
+++ b/util/cbfstool/partitioned_file.c
@@ -49,11 +49,13 @@ static unsigned count_selected_fmap_entries(const struct fmap *fmap,
 	return count;
 }
 
-static partitioned_file_t *reopen_flat_file(const char *filename)
+static partitioned_file_t *reopen_flat_file(const char *filename,
+					    bool write_access)
 {
 	assert(filename);
-
 	struct partitioned_file *file = calloc(1, sizeof(*file));
+	const char *access_mode;
+
 	if (!file) {
 		ERROR("Failed to allocate partitioned file structure\n");
 		return NULL;
@@ -64,7 +66,9 @@ static partitioned_file_t *reopen_flat_file(const char *filename)
 		return NULL;
 	}
 
-	file->stream = fopen(filename, "rb+");
+	access_mode = write_access ?  "rb+" : "rb";
+	file->stream = fopen(filename, access_mode);
+
 	if (!file->stream) {
 		perror(filename);
 		partitioned_file_close(file);
@@ -161,11 +165,12 @@ partitioned_file_t *partitioned_file_create(const char *filename,
 	return file;
 }
 
-partitioned_file_t *partitioned_file_reopen(const char *filename)
+partitioned_file_t *partitioned_file_reopen(const char *filename,
+					    bool write_access)
 {
 	assert(filename);
 
-	partitioned_file_t *file = reopen_flat_file(filename);
+	partitioned_file_t *file = reopen_flat_file(filename, write_access);
 	if (!file)
 		return NULL;
 
diff --git a/util/cbfstool/partitioned_file.h b/util/cbfstool/partitioned_file.h
index 2fc2bfe6b8..5a8f4dd5af 100644
--- a/util/cbfstool/partitioned_file.h
+++ b/util/cbfstool/partitioned_file.h
@@ -71,9 +71,11 @@ partitioned_file_t *partitioned_file_create(const char *filename,
  * caller, and must later be passed to partitioned_file_close();
  *
  * @param filename      Name of the file to read in
+ * @param write_access  True if the file needs to be modified
  * @return              Caller-owned partitioned file, or NULL on error
  */
-partitioned_file_t *partitioned_file_reopen(const char *filename);
+partitioned_file_t *partitioned_file_reopen(const char *filename,
+					    bool write_access);
 
 /**
  * Write a buffer's contents to its original region within a segmented file.