Unable to update J-Field on Victor-LS

From three days I have been trying to update J-Field on Victor -LS device without luck.
I have J-Field 2.0.3.855 installed on device.
In update panel I see that there are three updates available, GeoData, J-Field and J-Tip. When I choose 'Update' button, downloading process starts but transfer is very slow, only up to 30 KB/s and after a few percents, 'Loading update stage failed...' message appears. I tried two different network connections, at work and at home but update always fail.
 
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