diff --git a/src/fpgpio.pas b/src/fpgpio.pas
index 5c69c4d..55af49a 100644
--- a/src/fpgpio.pas
+++ b/src/fpgpio.pas
@@ -460,7 +460,7 @@ class procedure TGpioLinuxPin.WriteToFile(const aFileName: String;
 begin
   fd := fpOpen(aFileName, O_WRONLY);
   if fd = -1 then
-    EFOpenError.CreateFmt(SFOpenError, [aFileName]);
+    raise EFOpenError.CreateFmt(SFOpenError, [aFileName]);
   FpWrite(fd, aBuffer, aCount);
   FpClose(fd);
 end;
diff --git a/src/mcp23017.pas b/src/mcp23017.pas
index df0b00d..e720546 100644
--- a/src/mcp23017.pas
+++ b/src/mcp23017.pas
@@ -217,7 +217,7 @@ function TMCP23S17Controller.GetRegisterValue(aRegister: Byte): Byte;
 begin
   if HAEN then
   begin
-    b[0] := Address;
+    b[0] := Address or 1;
     b[1] := aRegister;
     fSPIDevice.ReadAndWrite(b[0], 2, rb[0], 3);
   end