I have a FS-i6 TX and FS-IA6B RX. Both are configured to work on i-bus on a omnibus f4 pro v2.
My stock firmware is - 2.0 16-Aug-2017

can some one please confirm below steps are correct?,

To flash custom firmware for 10 channels
Download FlySky-i6-Mod--master.zip from https://github.com/benb0jangles/FlySky-i6-Mod- and extract the zip.
Connext TX to pc using data cable.
Hold both sticks to bottom left corner and power on.
Select firmware update mode in TX.
Go to 10ch Mod i6 Updater -> 10ch_MOD_i6_Programmer_V1_5 folder launch 10ch_MOD_i6_Programmer_V1_5.exe
Select correct com port in 10ch_MOD_i6_Programmer_V1_5.exe and make sure that current version number is appearing.
click program, once 100%, turn off tx anad turn back on.

To revert back to stock firmware
Connext TX to pc using data cable.
Hold both sticks to bottom left corner and power on.
Select firmware update mode in TX.
Go to Firmwares -> Flysky i6 Original Firmware folder launch FS-i6-Original -Firmware.exe
Select correct com port in FS-i6-Original -Firmware.exe and make sure that current version number is appearing.
click program, once 100%, turn off tx anad turn back on.

Above steps worked. Except that, I had to use two left side trim switches holding them right and down and then turn on TX to enter firmware update mode.
I had to install usb to Uart data cable driver.
I also had to change com port number of my data cable from 10 to 3 as updater did not have 10 lusted.

Above steps worked. Except that, I had to use two left side trim switches holding them right and down and then turn on TX to enter firmware update mode.
I had to install usb to Uart data cable driver.
I also had to change com port number of my data cable from 10 to 3 as updater did not have 10 lusted.