Attenzione il cellulare si potrebbe danneggiare e si potrebbe

invalidare la garanzia

Procedere a proprio rischio...

Procedura provata con firmware: Z370XXGI1

Press:

   *#77686#

In order to go in "proto mode" (if the proto mode do not

appears then delete and re-press the "last" #)

press:

   1

in order to go in the Protocol value settings

press:

   volume down

in order to go to the 2nd "value settings" page

In  this page there are three values:

   1. 3g RRC VER. : R99

   2. SGSNR VER   : R99

   3. MSCR VER    : R99

   ...

   ...

press:

   1

in order to change "3g RRC VER." to R5

press:

   2

in order to change "SGSNR VER" to R5

press:

   3

in order to change "MSCR VER" to R5

press:

   the right soft key

in order to save your changes

restart the phone (turn it off-on)

when the phone restarts, if you connect to internet, the connection

should be HSDPA (no icon does appears but if you do a big download

you should note a speed higer than 384 kbps)