I asked my team to take a lookat the recent I2 firmware update. here is the comments we had

1) dont update anything until the updates for the DJI GO 4 are also available
2) always delete the older version of DJI GO 4 first before you downlod the new version
3) restart you mobile device before any update (If no DJI GO 4 update then move on to next step)
4) always have the I2 with camera fitted. If you have X5S then use this as i priority then repeat again with X4S later (DJI look for X5S first)
5) when the prompt is shown on the R/C that you need to update the firmware DONT do it with your mobile use only the Assistant 2 APP.
6) if the prompt says new firmware WAIT and look for new version of DJI GO 4 to be available before you do anything and follow steps 2 to 3 before you do anything
7) before you do any update connect to Assistant 2 and wait... if there is an intermediate update for such as battery do these first... and do it for all your pairs.
8) make you have a new set of fully charged BATTS and now download the new firmware. Dont go for a coffee but watch the messages... if you get anything not expected ABORT
9) even if the I2 reboots do it AGAIN
10) now power down and wait with no Batts inserted....
11) restart and watch... reboot follows normal ?
12) You have mopre than one camera? then replace camera and power down.. WAIT with no Batts fitted.
13) restart with full Batts  
14) go back to 7) above
15) if there is a camera update it will happen now.
16) OKAY so now you have new firmware on X4S and X5S... do you have the latest version of DJI GO 4?
17) did you read the release notes for this version of firmware?
18) so power up and enjoy...

I asked my team to take a lookat the recent I2 firmware update. here is the comments we had

1) dont update anything until the updates for the DJI GO 4 are also available
2) always delete the older version of DJI GO 4 first before you downlod the new version
3) restart you mobile device before any update (If no DJI GO 4 update then move on to next step)
4) always have the I2 with camera fitted. If you have X5S then use this as i priority then repeat again with X4S later (DJI look for X5S first)
5) when the prompt is shown on the R/C that you need to update the firmware DONT do it with your mobile use only the Assistant 2 APP.
6) if the prompt says new firmware WAIT and look for new version of DJI GO 4 to be available before you do anything and follow steps 2 to 3 before you do anything
7) before you do any update connect to Assistant 2 and wait... if there is an intermediate update for such as battery do these first... and do it for all your pairs.
8) make you have a new set of fully charged BATTS and now download the new firmware. Dont go for a coffee but watch the messages... if you get anything not expected ABORT
9) even if the I2 reboots do it AGAIN
10) now power down and wait with no Batts inserted....
11) restart and watch... reboot follows normal ?
12) You have mopre than one camera? then replace camera and power down.. WAIT with no Batts fitted.
13) restart with full Batts  
14) go back to 7) above
15) if there is a camera update it will happen now.
16) OKAY so now you have new firmware on X4S and X5S... do you have the latest version of DJI GO 4?
17) did you read the release notes for this version of firmware?
18) so power up and enjoy...