Originally Posted by kRt_uK
1- The chipset Intel (Infineon) XMM6260 is built-in on Nexus 7 3G (the same chipset is in that rather long list of phones). It means no hardware limitations.
No it doesn't. There are many ways in which the XMM6260 audio I/O interface can be wired (just look at the Galaxy S2 family of devices - all have XMM6260 but the audio configuration in terms of which device is master/slave and sample rate is significantly different for each device) including NOT WIRED AT ALL. The 6260 also is just the BASEBAND and usually has a bunch of support chips (power amplifiers, RF frontends, etc.) hung off of it - so unless you can get a device which has a hardware configuration (RF frontends, PAs, audio routing) that is an EXACT match to that of the N7, you're going to fail.
Maybe it was wired up, maybe it wasn't - even if physically wired, there's a good chance the radio firmware (baseband) might not enable the port at all.
XMM6260 basebands are RARELY portable. Even with devices with FAR more commonality than N7 does with anything else, modem swaps fail.
For example, the SGH-I777 (AT&T Galaxy S2) and GT-I9100 (International GS2) are 99% identical. You know what one of the differences is? Call audio fails completely if you flash an I9100 baseband to the I777.
I have never, in my entire time here, ever seen a successful XMM6260 baseband swap succeed. Plenty of people tried to do so with the original Galaxy Note (GT-N7000) to try and enable T-Mobile UMTS1700 support.