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"Signature check" error when updating EMX to v4.2.11.1


I need to update the EMX module to the latest firmware in SDK v. 2013 R3. This is the current configuration as displayed by FEZ Config:

Loader (TinyBooter) version information: on this computer. on this device.

The Loader (TinyBooter) not up to date. <<<

Firmware (TinyCLR) version information: on this computer. on this device.

The Firmware (TinyCLR) is not up to date. <<<

When I run MFDeploy to perform the update, I get: “Error: Signature check failed for file Config,sig”. See attached image. I am fetching Config.hex, Firmware.hex and Firmware2.hex from “GHI Premium NETMF v4.2 SDK\EMX\Firmware”. I can deploy the old hex files without any issues --it’s only with the new files that I get the signature error.

I would appreciate any suggestions. Thank you.


Did you update the TinyBooter firmware before the TinyClr firmware?

If you have the latest SDK, then you should use FEZConfig to load the TinyClr firmware.


I just tried updating the EMX TinyBooter with FEZConfig. I click Advanced > Loader (TinyBooter) Update > EMX (Fez Cobra). I set the file to: “GHI Premium NETMF v4.2 SDK\EMX\Firmware\TinyBooter\TinyBooter.GHI”. When I click Next, it jumps to the EMX Updater menu, which automatically fetches: Config.hex, Firmware.hex and Firmware2.hex. When I click next it returns this error: “The Loader cannot be updated if more than one device is connected. Make sure that only one device is connected and that it is in bootloader mode.” I don’t have other devices connected to the EMX. I am not sure how to put the EMX switches in Loader configuration. The document titled “Loader (TinyBooter) G120 and EMX Families” says “EMX: Ground pins 7, 3, and 53 then reset or power cycle the device.” I cannot locate these pins. I do have Up/Down/Reset…etc…buttons in the back of the board.

Any suggestions? Thanks in advance.


Thanks. FEZ Config does confirm the device is in Loader mode although I still get the same error when I try to update TinyBooter. I am wondering though if the Invalid Signature error I get when updating the EMX firmware from to is actually caused by the TinyBooter.


Yes, I uninstalled all the files. I just tried installing SDK 2013 R2, which is one version older than what I’ve been using, and I’m getting the same results. I wonder if the Loader error I get in FEZ Config is an issue with the USB driver. I read that there are different USB drivers which are being used. I am reading another way to update TinyBooter is via TeraTerm. I am connecting to COM1 and I’m not seeing anything from the serial port.

Baud rate: 115200
Bus width: 8 bits
Parity: none
Stop bits: 1 bit
Flow Control: none


The EMX is now up to date. To update the TinyBooter, one has to power up the EMX while pressing Up, Down and Select.