G400D bootloader only presents COM port and never flips over to USB

I’ve got two G400D modules that only present a GHI Bootloader Interface COM port when booted up… No matter what I try to get TinyLoader loaded/working the board only presents the GHI bootloader as a COM port. I’ve tried using the FEZConfig and the Flash Bootloader.bat to load TinyLoader to no avail. Both modules are showing v2.0.1 of the Bootloader being loaded when queried with TinyCLR Config, but when trying to load “loader.ghi” dated 3/24/2016 the app will show the progress and then fails saying the uploaded file is corrupt. So either my loader.ghi it truly corrupt or I’m not performing the steps in the right order to get these units working. My app requires NETMF v4.3.

do you have other G400D’s that behave the right way? If so, then can you spare one for “science” and see if you can reapply the GHI loader and firmware as you normally would - this basically proves that the software you use to deliver the firmware is working.

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Yes, I have another G400D that I could experiment with… I just didn’t want to brick another one should I perform the load improperly.

If the board starts in GHI Bootloader mode, can you try to load TinyBooter using a program like TeraTerm instead of FEZ Config? Also reinstall the NETMF SDK to make sure you have an uncorrupt version of TinyBooter.

I did try to use TeraTerm and when TeraTerm starts to perform the XModem 1K load it hangs after sending the first 1K to the G400D. I’ve made several attempts to load both of them via TeraTerm (even using another computer) and it always hangs on the first sent packet until it times out. I get the repeating C’s from the G400D, but XModem just won’t load it.

Is this all with the latest 2016 R1 SDK (

Yes, that is correct.

Since it is the D format you can easily swap old and new modules to compare and verify the problem is not related to your board. I would also get an old functional board and try to erase and flash to verify your computer is not the problem.

Gus, it isn’t a board issue… I’m using the G400D that doesn’t work on the same board that a good G400D does work on… What are the steps to erase the flash and reload it? I’m not sure that I have a clear understanding of the exact instructions.

Using the samba tool from atmel, you can manipulate the dataflash. To put the board in samba mode you need to ground one of the pins. Please check the old datasheet and the page http://docs.ghielectronics.com/hardware/ucm/g400d.html