Improve flashing STM32 with JTAG (#72)

Author: josesimoes

nanoFirmwareFlasher/StmJtagDevice.cs

@@ -10,6 +10,7 @@
 using System.Linq;
 using System.Text;
 using System.Text.RegularExpressions;
+using System.Threading;
 
 namespace nanoFramework.Tools.FirmwareFlasher
 {
@@ -100,6 +101,9 @@ public ExitCodes FlashHexFiles(IList<string> files)
                 return ExitCodes.E5003;
             }
 
+            // need a couple of seconds before issuing next command
+            Thread.Sleep(2000);
+
             // try to connect to device with RESET
             var cliOutput = RunSTM32ProgrammerCLI($"-c port=SWD sn={DeviceId} mode=NORMAL");
 
@@ -229,8 +233,11 @@ public ExitCodes FlashBinFiles(IList<string> files, IList<string> addresses)
                 }
             }
 
+            // need a couple of seconds before issuing next command
+            Thread.Sleep(2000);
+
             // try to connect to device with RESET
-            var cliOutput = RunSTM32ProgrammerCLI($"-c port=SWD sn={DeviceId} mode=UR");
+            var cliOutput = RunSTM32ProgrammerCLI($"-c port=SWD sn={DeviceId} mode=NORMAL");
 
             if (!cliOutput.Contains("Connected via SWD."))
             {