diff --git a/twrp-functions.hpp b/twrp-functions.hpp
index d49cd84..d72c916 100644
--- a/twrp-functions.hpp
+++ b/twrp-functions.hpp
@@ -85,6 +85,7 @@
 	static std::string to_string(unsigned long value); //convert ul to string
 	static void SetPerformanceMode(bool mode); // support recovery.perf.mode
 	static void Disable_Stock_Recovery_Replace(); // Disable stock ROMs from replacing TWRP with stock recovery
+	static unsigned long long IOCTL_Get_Block_Size(const char* block_device);
 
 private:
 	static void Copy_Log(string Source, string Destination);