[GitHub] [C6506] [XperiaZL] Please update codebase. Custom ROMs kill LTE/HSPA

[petenj]

Hi. All of the custom ROMs and Sony's own source for the Xperia ZL C650X are based on the published codebase on GitHub for the C6503. When installed, important HSPA and LTE frequencies are lost. In the US, this kills T-Mobile compatibility for all but EDGE.

Can you please publish a code branch for the C6506 so compatibility is maintained. Thank you

Here is what gets lost

GENERAL

2G Network	GSM 850 / 900 / 1800 / 1900 - C6502, C6503, C6506
3G Network	HSDPA 850 / 900 / 1700 / 1900 / 2100 - C6502, C6506
	HSDPA 850 / 900 / 2100 - C6503
4G Network	LTE 700 / 850 / 1700 / 1900 / 2100 - C6506
	LTE 800 / 850 / 900 / 1800 / 2100 / 2600 - C6503
SIM	Micro-SIM
Announced	2013, January

[Uliwooly]

Why don't you flash the correct firmware and then flash the different firmware but this time exclude the baseband, the original LTE frequencies should work. 

[petenj]

I thought about that. I was concerned about mixing apples and oranges. So you recommend,

1. Flash NEW ROM,
2. Flash Baseband from stock?

I have the Clean FTF for my device from the FILEs.

Confirm, and I'll give it a whirl.

[Uliwooly]

let me see if I understand, you have a custom ROM but LTE and H aren't working, what about with a regular Sony's firmware? 

Also if you have the C6503 you can flash the C6506 firmware but its not going to change the 3G nor LTE bands it will remain on the C6503's

[petenj]

On review, ROMs like Cyanogen, AOKP, just update the /system directory and offer a boot.img which writes the kernel and recovery on the boot partition.

I can always revert to stock again and relock bootloader if performance is too poor.

Thx

[petenj]

Thc C6506 has unique bands frequencies for H and LTE. See table above.

[Uliwooly]

I am aware of that, but which Xperia do you have C6506 or C6503?

[petenj]

Of course I have C6506. I want those frequencies. There was a note in Cyanogen about this being a known issue. I believe it can only be corrected through code in /system. The baseband should be unaffected by adding a custom ROM. IMHO.

[petenj]

OK, so as expected, the custom ROM changed the model number to C6503 and did seriously reduce the frequencies. So I hope Sony will update their codebase to include C6506. FYI, once custom ROM is installed, the service menu is not accessible anymore by *#*#service#*#*. The code *#*#4636#*#* will get to a service menu. Baseband did not change. Fortunately, T-Mobile is using the PCS bands and with their merger of MetroPCS I can still get LTE on 1900.

Image 1: Post ROM insertion System info

Image 2: C6506 Native Bands offered

Image 3: Post ROM insertion Bands Offered

[jd_khan]

Screen short option is not available in my ZR aftr updating the software