When the webupdate of the MCH fails during upload of the image, the MCH might be in a kind of emergency state. In this case only the bootloader is started, where access only via the serial connection is possible. The reason for this is, that the webupdater will set the boot string to be 0, what means, that after the boot loader no firmware is loaded. After successfull upload and installation of the new f/w, the webupdater would change back to the correct boot string (0xd0100008) and do re reboot.

In case of a broken update, the only way out is to upgrade the f/w via the command line on the serial port. The update_firmware command has to be used. Then it will ask for the IP address and file name. For this purpose a tftp had been installed and started on exflutcadev (192.168.81.200). So the procedure works as follows:

Connect to serial port via the USB cable on the front on the MCH.

> update_firmware

> 192.168.81.200:mch_fw_214_1.bin

The the upload and upgrade will be done. If it was successfull:

> bs

> 0xd0100008

> yes (if it is asked for it)

Finally do a power cut