I've found this setting in the "Advanced Setup"
(P.S. it is a bit misleading that have i turned all the knobs off there were still some active protections....)
Anyways, after i've disabled Protocol Filtering - only first 2169 bytes are being downloaded...
@itmanI fully acknowledge the security issue here. The JNLP file is accessed via HTTP, the rest is downloaded via HTTPS. Nevertheless, i think i should not uninstall ESET if i want to use my unsecure stuff, right?