diff --git a/BIOS/T431s.FL1 b/BIOS/T431s.FL1
new file mode 100644
index 0000000..f2523df
Binary files /dev/null and b/BIOS/T431s.FL1 differ
diff --git a/downgrade.bat b/downgrade.bat
index ac86491..d877e17 100644
--- a/downgrade.bat
+++ b/downgrade.bat
@@ -24,5 +24,6 @@ if "%model%"=="ThinkPad X230  " winflash64 /sd /file X230.FL1
 if "%model%"=="ThinkPad X230 Tablet  " winflash64 /sd /file X230t.FL1
 if "%model%"=="ThinkPad T430  " winflash64 /sd /file T430.FL1
 if "%model%"=="ThinkPad T430s  " winflash64 /sd /file T430s.FL1
+if "%model%"=="ThinkPad T431s  " winflash64 /sd /file T431s.FL1
 if "%model%"=="none" echo No compatible model detected. Exiting.
-pause>nul
\ No newline at end of file
+pause>nul