Tom Haynes

Any progress recreating (and fixing) the original issue?

I have not tried to recreate the problem yet but it appears that Chris' statement about tight loops applies to my original cause. I had a very short program that checked for data in the serial buffer and printed it out to debug. Originally, I had a 100ms sleep in the loop but had commented it out in the last revision. If there is no data in the serial buffer the only step in the loop is to check the buffer. I will add the sleep timer back.

If you hold the pushbutton on your Netduino Plus while plugging it into your PC, it should stay in TinyBooter mode for 5 seconds. If you PING the device from MFDeploy during those five seconds, it'll stay in the bootloader for at least 20 more seconds.

===== SOLVED =====
All it took was a little better description of the reset procedure. Thanks Chris. I was holding the button for several seconds while powering up and then trying to ping. I offer the following instructions for others who are as lost as I was.

-- Erasing apps from Netduino or Netduino Plus using MFDeploy
This procedure only erases the apps space of the Netduino. It will not erase the Firmware or the Bootloader. You should use this procedure if you can no longer talk with the Netduino using Visual Studio or MFDeploy. The Netduino must still show up in Windows Device Manager (Start->Run->devmgmt.msc) under Universal Serial Bus Controllers as Netduino and in MFDeploy as USB->Netduino_Netduino or USB->NetduinoPlus_NetduinoPlus. If not, you have other problems.

What you need to complete this task:
1. Netduino or Netduino Plus
2. USB cable that fits your Netduino
3. MFDeploy.exe
Click on Start->All Programs->Microsoft .NET Micro Framework 4.1->Tools
This will open a folder where you will find MFDeploy.exe, if you are hiding known extensions the file will be called just MFDeploy. (MFDeploy.exe.config shows up as MFDeploy.exe if known extensions are hidden)
If you don't see Microsoft .NET Micro Framework 4.1 you missed step 2 of installing the development environment. Go here and follow the steps in the top left corner of the page.

Preparing to complete this task:
Since all of the steps are time sensitive, you will need to have everything ready to be able to act quickly.
1. Open MFDeploy.exe
2. In MFDeploy under the Device section, change the left most drop down box from its default of Serial to USB
3. Place your mouse over the Ping button but do not click it yet. You will only have 5 seconds to click it when the time comes.
4. Plug the USB cable in to the computer but not the Netduino

Completing this task:
All actions are time sensitive. You will only have 5 seconds to complete the first steps to enter TinyBooter and then only 20 seconds to complete the remaining steps.
1. Remove all cables plugged in to the Netduino (There is no time limit on this step)
2. While holding the button on the Netduino down, plug the USB cable in. Continue holding the button until after step 4.
3. Within 1/2 a second, the Netduino should show up in MFDeploy between the USB drop down and the Ping button. If it does not appear, your USB cable may be bad.
4. Press the ping button within 5 seconds of the Netduino appearing in MFDeploy. The response should be "Pinging... TinyBooter"
If you see only "Pinging..." then the Netduino is not responding. You may have been too slow, Try again.
If it still fails, try releasing the button after the Netduino appears in MFDeploy but before you press ping. The button could also be bad and therefore skipping the TinyBooter stage. Try testing the button with an ohm meter.
If you see "Pinging... TinyCLR" you were too slow or but the Netduino is working fine and should not be having any problems.
You can skip this ping step and go straight to Erase but then you will only have 5 seconds, instead of 20, to press Erase and click Yes in the confirmation window.
5. You now have 20 seconds to press the Erase button
6. A confirmation window will open asking you if you want to erase the application and data. Click Yes.
7. You will see a status bar in a popup window. When the window closes the erase is done.
If you did this from TinyBooter then the closing of the status window is all you will see. Continue to step 8.
If you did this from TinyCLR, on purpose by not holding the button during power up or from being to slow, the Netduino will tell you it is rebooting and you will see a bunch of details about the software environment fly by.
8. Reboot the board by unplugging the USB cable and plugging it back in. If you press ping after a couple of seconds you should see "Pinging... TinyCLR". The erase worked and you can continue your work.

Is your network cable plugged into the Netduino Plus?

No Ethernet, no power, no uSD card. Only USB.

To clarify, I don't want to wipe the firmware it just seems to be my last option. I wanted to be able to load apps again. I tried holding the button when connecting the board but tinybooter never starts and hitting erase in mfdeploy just hangs until I unplug the board. Something is working since the hardware is recognized by windows and mfdeploy.