How to upgrade Connectport X2 from ZB to 802.15.4

I’ve been using my old Connectport X2(D) ZB for years, absolutely happy with it. However now I’m working with tiny Texas Instruments microprocessors using 802.15.4 as communication protocol, and I would like to use my ConnectPort as coordinator.

I’ve updated successfully the gateway firmware to version, but when trying to update the radio module firmware, gateway tell me that only .oem files are suitable to be used for upgrading it, however the only firmware upgrade files I can find are in .ehx and .ehx2 format.

I read in the "“Xbee firmware filename conventions” document (link that XCTU can be used for converting .ehx files into .oem, however I am not able to find the way to do it (at least in the MacOSX XCTU version).

Could someone tell me where is that option, please?

Thanks in advance.

UPDATE: My Connectport X2 gateway comes with a XBee Pro S2 radio module, and after trying different approaches (updating via gateway and via XBIB+XCTU) it seems that this module is not compatible with 802.15.4 firmwares.

Therefore the only valid option seems to be replacing the stock S2 module by a S1 or S2C module. Since the question changes to a new one regarding gateway devices, I will ask in the right forum if the X2(D) gateway is compatible with S2C radio modules.