I have modules which the device doesn’t boot properly.
I been trying to use recovery mode and get to APX driver. However following the article on your website I can’t get to APX driver to re-flash the OS image.
I have Evaluation board V 2.1. Is there any other way apart from connecting the pads on T20 itself to get to APX?
Instead of shorting the pads on the module, you can pull SODIMM pin 91 (OE#) to GND. On the later versions of the Evaluation Board, we introduced a recovery button for this purpose (refer to the Evaluation Board V3.1 schematics for reference)
The recovery mode (APX) is probably not working because of the USB circuit on the Evaluation Board V2.1. In this old version, USB was designed to work at full speed only (12Mbps). The circuit is not able to carry the high-speed signals (480Mbps).
However, you can remove / replace a few components to make the Evaluation Board V2.1 compatible with the high-speed signals. Please refer to the following article for details:
When modifying the Evaluation board to work with high speed USB, in the link it is written that “You can not use the board in detection mode with this setup any longer (all three pins connected).”
Does this mean I cannot use USBB port to connect to my PC via a USB A to B cable?
The USB-B port is still the interface to use for a connection between your PC and the Evaluation Board V2.1.
The note is about JP8/JP9:
In the original configuration you can connect all 3 pins of these jumpers, and then connect either a USB-B cable, or a USB-A device. After the modification, you will need to put the jumpers to the 2-3 position when you connect a USB-B cable, and to the 1-2 position when you connect a USB-A device.