help signal increasing China GT-i9300

[exmarinaio]

Who can recommend me kindly?
I received these days a Chinese i9300 Android 4.8 display "single SIM.
Operation-download applications, GPS, video and display-all OK according to my needs.
Primary drawback is the difficult and intermittent signal reception UMTS 3 Italy, the operator with which I have no problems in any situation with the smartphone Nokia Xpress Music 5300.
I think it can be resolved by updating the modem but I could not do.
I downloaded and unzipped the file and Odin3_v3.04 modem_I9300NEDLI1_TRE PC.
I connected the 'i9300 confirmed via USB mass storage as required (but I tried also with only the download folder open without confirming the mass memory) and Odin open on your PC. In the phone menu I loaded the modem.bin as above and press Start.
Nothing seems to have happened.
Odin appears on the screen: <OSM> all threads completed. (succeed 0 / failed 0), that is, it seems to me that Odin PC does not see the phone for which data are:
GT-i9300
Android version 4.1.9
Baseband version MAUI.11AMD.W11.50.SP.V20
2012/08/13 14:56
Kernel Version 3013
1211 V58
Wed.Jan 2 16:36:33 CST 2013
Build Number IMM76D.GT-I9300ZSALE9
Customized version buil 1357097495
My questions are for you practical and leading experts:
1 - To improve reception 3 Italy is my interpretation correct proceed to upgrade the modem and the files I have downloaded are the right ones? Only the modem.bin as I have done or do I recover the file system full?
2 - How exactly do point to point connection between PC and Smartphone?
I will be much obliged response even if the possible negative impossibility of development.
Thank you all.

 

[Hadron]

Hi exmarinaio, and welcome to AF

I'm afraid that I can tell you why Odin doesn't recognise your phone: it isn't a Samsung S3. The real test is the baseband: that baseband is not a Samsung one, but it is one that is found on Chinese clone handsets. You'll need to find software for that actual handset model in order to update it - if you could install a Samsung baseband on it (which luckily it won't let you) it would brick the handset for certain.

Unfortunately support for these handsets is limited. This XDA thread discusses rooting a phone that sounds very much like yours - most of the numbers match apart from the custom version. I've not read it all though so don't know whether it discusses baseband updates, or even whether those (or tools for updating them) are available for this handset.

I'm sorry to bring bad news.