T770 firmware update issue

[MicGus]

Hello,
The update to version TT6-TTAJ_08_02_03.3.90 seems to have taken place correctly but the version displayed remains 7.0.1.2.

I proceed with the web server. After the download the screen displays:
 1% 2% 3% 4% 5% 6% 7% and 100% 
The size of file I am using is 3.61Kb !! 
I downloaded it from support.hp.com. 
Where is my mistake? 

T770 N ° CN9CK2H04
Firmware: T6-TAJ 7.0.1.2
Product number: CH539A

Thank you for your answers

[Valsimot]

The firmware is 457MB, check readme file for instructions

https://support.hp.com/hr-en/drivers/selfservice/hp-designjet-t770-printer-series/3980523 

[MicGus]

Thank you for your response. I won't be able to test until next week. I'll keep you informed.