This is a common error when playing online or playing videos (i.e. replaying tracks) with HSFX / Ultrapack installations.
The reason is that these packs include some mod which alters the AircraftState class.
In the "netFirstUpdate" function of this class, that specific mod adds some additional aircraft state initializers, whose states it has to read from a net stream when playing online or replaying tracks (sidenote: Replaying tracks internally means nearly the same to IL-2 like playing online).
Now that there are additional initializers trying to read values from the net stream, there might be situations where the server version of the AircraftState class doesn't match the client version, or for track playbacks, where the track was recorded without those additional initializer parameters (to make things worse, UP2.01 records tracks without them, but tries to playback with them).
To avoid errors like this, usually one would check whether or not additional init values are available in the net stream before attempting to read them.
The "netFirstUpdate" in UPs AircraftState class does this most of the times, too, but unfortunately it misses this security check on the last two initializers:
(...)
setAirShowSmokeType(netmsginput.readUnsignedByte());
setAirShowSmokeEnhanced(netmsginput.readUnsignedByte() == 1);
(...)
To avoid the EOFException, these lines should look as follows:
(...)
setAirShowSmokeType(0);
setAirShowSmokeEnhanced(false);
if(netmsginput.available() == 0)
return;
setAirShowSmokeType(netmsginput.readUnsignedByte());
if(netmsginput.available() == 0)
return;
setAirShowSmokeEnhanced(netmsginput.readUnsignedByte() == 1);
(...)
Since I don't know who modified the AircraftState class or which mod the UP2.01 version of this class is part of, I unfortunately cannot address this corrections to the right place.
The only thing I can tell atm is that with 4.10 things will change completely, since the "netFirstUpdate" function, together with a set of other functions from AircraftState class, has been completely rewritten.
Best regards - Mike