diff --git a/adb_utils.h b/adb_utils.h
index b38ec59..b9da980 100644
--- a/adb_utils.h
+++ b/adb_utils.h
@@ -31,7 +31,7 @@
 
 std::string escape_arg(const std::string& s);
 
-void dump_hex(const void* ptr, size_t byte_count);
+std::string dump_hex(const void* ptr, size_t byte_count);
 
 // Parses 'address' into 'host' and 'port'.
 // If no port is given, takes the default from *port.