[Xperia Z Q&A, Help & Troubleshooting] lhun:
http://www.xda-developers.com/andro...tmctr=(not provided)&__utmv=-&__utmk=63603752

It's been figured out, I speculated it was possible, and it is!

Preamble

Hi everyone. As we know, the C6603 (all country versions) can be swapped with the radios from the ZL. This allows you to get LTE on Rogers and Fido in Canada, and I assume would work for other carriers as well in other parts of the world. (this is due either to unlocking frequencies, or unlocking channels on those frequencies.)

The radio HARDWARE is the same. *(?!? is it?) From what I understand the baseband chip in ALL the devices is a:

Qualcomm MDM9215M

which fully supports all the bands we can possibly use. Meaning, this device CAN use UMTS 4 1700/2100 for T-Mobile and Wind and Telus etc etc.

The secret is the amplifier chips. If the c6603 has the amplifier chips physically that the c6602 does we should be able to do the same trick that was done on the nexus 4. A modification of the build.prop may allow for AWS networks to work on our c6603. We can only hope. Partial support to at least use the AWS bands should be possible for the 6603. You would have to do the same thing that was done for the google nexus 4. Essentially,

#!/sbin/sh

echo "telephony.lteOnGsmDevice=1" >> /system/build.prop

echo "ro.telephony.default_network=9" >> /system/build.prop

echo "ro.ril.def.preferred.network=9" >> /system/build.prop

And then flash. Obviously requires a rom cook and root. If any intrepid developers wants to give this a shot, I suggest using the 6606 baseband, as it seems to be both a 6602 and 6603. The 6616 is essentially the same as the T-Mobile phone but with Canadian channels.

Why I care

When the Z first came out, I knew I needed to have it. By a terrific stroke of luck a local had bought an unlocked international Belgum phone off ebay and decided he wanted the S4 instead. He was selling it for hundreds below the MFG price on Kijiji. I immediately bought it. I love the phone, but I can only get 3g, as I am with Telus, and the phone "doesn't support" officially, AWS on Telus. Works with HSPA+ for whatever reason though, on non aws bands.

New knowledge not currently found on the forum

Bell uses AWS on HSPA+ as well as LTE. So does Telus, and Wind. (and Tmobile in the US)

Historically, only the C6602 has the frequencies needed for the other carriers. Bell, in Canada, recently released the C6616.

(LTE compatibility AWS, 700 MHz HSPA/UMTS compatibility 850/1900/1700/1900/2100 MHz GPRS/EDGE compatibility 850/900/1800/1900 MHz)

The question with no answer.

The question is: Can I apply the Baseband file from the Bell C6616 phone to get AWS 1700/2100 hspa/LTE on a C6603?

NEW!

Note: I'm not rooted, nor am I bootloader unlocked. Neat, eh?

Here's what basebands I've tried so far: (c6603 Generic BE, .67, 4.2.2)

c6506 US .434, c6506 US 0.423 - both work perfectly on 4.2.2, no issues. On Telus you can only see Telus, and AT&T, sometimes Rogers.

c6606 - Phone boots, unusable. Random reboots, locks up immeditely after swipe to unlock. Simply flashed baseband back to c6506. - This may be because I was using a 4.1.2 rom. I'm going to re-investigate.

c6616 - Phone boots, slightly usable. Random reboots, even in airplane mode. System.process freezes but eventually unlocks. If you screenlock, you need to reboot. Flashed it back to c6506 (probably due to 4.1.2 again)

ZL c6502 .434 global unbranded - Phone boots. RADIO SHOWS - (!!!) Phone completely usable. OMG I CAN SEE BELL 3g and ROGERS LTE (which is 2600mhz!). Something interesting is going on here, but it's not unlocking any additional bands in reality. The *#*#service#*#* menu shows the same frequencies available - but there's CERTAINLY some modification to the ranges in the bands. For those of you using .434 c6506, switch to c6502 global, you might get better speeds. Woot!

Z c6602 .67 Works. 2g, 3g bands including LTE (on 2600 only I'm sure) available but only on Rogers my home network, Telus, comes up as 3g H+. Cannot see Wind but that might be due to not having a wind Sim at the moment T-Mobile comes up as 2g only. I believe it uses umts 4 for 3g/4g. Essentially the same as c6506.

c6606 0.191 - phone slightly usable. Still has issues with random reboots. Won't go into info or network menu at all. This sounds like mismatched build.prop... this might be possible. Exciting.

MORE MAGIC FOUND.

The info menu (*#*#4636#*#*) *#*#info#*#* allows you to swap country mode frequency ranges (including an UNKNOWN range on)!! This greatly impacts the available networks you see when you scan for networks in the phone. With USA selected I do NOT see T-Mobile, for example, when previous I did. Needs more playing.

I'm not sure it will work at all, apologies if this has been explored. The phone only supports limited UMTS bands. In particular, it would need to say UMTS 4, 9 or 10 in that list, I think.

Originally Posted by kingvortex View Post

The C6602 does not have an LTE capable radio. I'm not sure where you heard that it does, but that information is incorrect. There is no way for you to use LTE on your device, no matter which baseband you may flash.

This is correct, sort-of. It turns out that the radio hardware chips themselves are actually the same, but the unit is missing the physical amplifiers for the frequencies you would unlock, making them impossible to use. It's the c6603 radio hardware that has euro LTE. However, the 6602 is supposed to support AWS in some fashions. If you flash the baseband from the bell Z, you may be able to use AWS 4, because it's not just the frequencies that you make available, it's the CHANNEL SET.

In summary a "baseband" is three things

1) radio driver

2) frequency range list

3) channel range list

In theory (logically), the baseband from the "unbranded sony store" phones of each hardware model variant should have all the carrier frequencies of the local area.

So, if you're from Germany, flashing a the Sony "carrier unbranded" baseband from the local model variant should allow you to be all all carriers in that region because it would be in Sony's best interest to sell an unlocked phone in that region in that way.

It gets dicey when you bring a phone from another country as I did, into a country that uses different radio frequencies and channels for the same wireless protocol types. It's complicated and has to do with the radio telecom standards differing in every country. True "World Phones" are really uncommon but we're getting more standardized every year.

I still own my Z but I also have a Z1. The Z1 is a LOT more compatible (every carrier in my area) because it's designed to work with local frequency sets. All I had to do on it was flash the Sony official firmware and baseband, and I could get LTE on every carrier.