I tested TCP Modbus Slave with the firmware RUT9XX_R_00.06.05.1. All was fine between the registers 1 to 184 (only I found some mistakes in some registers). When request the registers over 185 (i.e. the registers with the info of the SIMs) I received error from modbus that device not support this registers.
I Updated to the last firmware (RUT9XX_R_00.06.06.1), and now the THE TCP Modbus Slave is not working, after one query I received error, and I need to wait several seconds. And now, there are a lot changes in the registers. Only some variables maintain the same registers.
when you will fix the issues with the modbus Slave?