Currently we investigated that the modules were detected, but only if a 2nd try was started to connect the modules. For us it seems that the communication is only established indirectly and for some specific reason not with the first try. Independently of the back plane which is used to place the modules to connect to the host. We tried either the SparkFun XBee Explorer and the XBee Grove Dev. Board.
For us the solution was to load the correct firmware on the module, by browsing through firmware explorer.
The firmware working for that module is:
Product family => XB24C
Function Set => ZIGBEE TH Reg
Firmware version => 4059
This firmware can be loaded by going to update firmware after the connection is made or by going through advanced options at the start even when XCTU couldn’t detect it automatically.
Make sure to check the option “Force the module to maintain its current configuration” in the firmware selection window.
I have a problem just like yours. I have same model of xbee and my xctu is 6.3. Please tell me step by step how you solved it, I could not understand what you did to solve.
What I would do is open a terminal window on the same COM port but enable the break and assert RTS. Then hit the rest button on the interface board. deselect the break and issue a . A menu will come up. Pressing B will put you in bypass mode. Once in bypass mode, use the same steps as before to write the new firmware to the module.
I had problems with some s2c modules too (some worked just fine). In my case it turned out that those that didn’t load in XCTU needed legacy-firmware support (Firmware version 4059). After downloading and installing the legacy firmware, the modules where detected properly and I was able to upgrade and configure the modules.