There were some minor glitches in the 7.3 bootloader. I have provided a link to a site that has all available patches for 7.3. I would recommend loading (at the minimum) the following patches:
1. BSP Updates
2. FTP Updates
After loading the patches, open the ESP and rebuild your project.
If you need to recover your module and are having difficulty, try the Xmodem recovery method I have outlined below for recovering the module.
The recovery method described here are assuming the module is plugged into a Digi development board. When we reference certain pins to be jumped, we are referring to specific pin headers on the development board.
We currently have two styles of development boards. On the older dev board, we are referring to the "MFG" or P5 pin header located next to where the module plugs in. On the new dev boards, the pin header is designated as P9.
Shorting the "/init" pin (pin 20) and the "MFGI" pin (pin 18) to ground, power up the module, and watch for the message "Starting Recovery..." on the serial port at 9600/8/n/1 no flow. Once you see the "C"s creeping across the screen then the module is now ready to receive the new image via the serial connection.
Now, open an Xmodem connection via the serial port to the Digi module (9600 baud, 8 data bits, no parity, 1 stop bit, no flow control). Hyperterminal in Windows will have this capability. The module should show the progress and the image is transferred via serial to it.
Once the image is finished being transferred, the module will write it to it's flash chip. This process may take a minute or two. After this is finished the module should reboot and execute the uploaded image.
NEW style development board:
For doing a recovery using the "NEW" development board, two sets of pins need to be jumpered.
1. Turn off power switch on development board.
2. On the twenty pin header labeled "P3" (located to the left of the ME module, next to the two pushbuttons), jumper pins #16 and #20.
3. On the 4 pin header labeled "P9" (located close to the power connector), jumper pins #3 and #4.
4. Turn on power switch.
5. Watch the output of the serial port, continue remainder of recovery procedure.