Use RN2483 on India IN865 LoRaWAN band

In Node RN2483 (1.01) , the channels 0,1,2 are fixed with 868.1 868.3 and 868.5 Mhz frequencies and apparently cant be changed.These 0,1,2 are also the channels which are required for a join/response request in case of OTAA .

I have to use IN_865_867 band so I have set the 3 compulsory Indian frequencies( 865.0625 , 865.4025 , 865.9850 MHz as specified in the regional parameter documentation ) at channels 3,4 and 5 ( setting the freq , data rate range , duty cycle and enabling the channels ) .
I also have disabled the channels 0,1,2 .

ABP works fine . But for more security I would like to use OTAA.

The problem is that I am unable to join the network using OTAA : it returns no free channel as its response. I think this is because it only accepts channels 0,1 and 2 for its join request so it is not even considering the channels 3,4 and 5 which are ON and thus showing no free channels.
So how do I get my end node to accept these channels as well for the join request so that OTAA activation works?
Really appreciate any HELP .

I think the best option would be to request a firmware for the India band from Microchip (the vendor of the RN2483).

But does that mean that with this current firmware(1.01) in RN2483 its not possible to join with OTAA using Indian frequencies and can only be joined utilising the default 0,1,2 channel EU band freq ?