[Z550i] Tri-band to Quadri-band

[gmichels]

Hello,

I recently switched carriers and unfortunately my new carrier uses GSM850, so my current Z550i, which is tri-band, doesn't support its network natively.

I found on the net some ways to make a SE phone become quad-band, by applying this patch:

gdfswrite:000000AC12

Accessing the service menu, I can see the patch was succesfully applied, since all 4 frequencies are now displayed there, instead of only 3 before the patch. Still, the phone can't find my carrier's network and stays in 'Searching' then in 'Emergency Only'. Doing a network scan doesn't yield any results other than 'No network coverage' (may be different, it's a free translation from my language).

Here's the setool2 log, including when I applied the carrier unlock patch:

Welcome to SEtool2 ( LITE edition ) v 1.11
supported DB2010/DB2012 CID49/50/51/52, DB2020 CID49/51/52
Loaded 51 flash descriptors
 
if you like LITE edition - please visit www.setool.net and buy FULL.
 
ChipID:8040,EMP protocol:0301
PHONE IS RED RETAIL PRODUCT
FLASH CID detected:49
Speed:921600
Flash ID check:2019
Flash props sent ok
OTP LOCKED:1 CID:49 PAF:1 IMEI:35*********** CERT:RED
FLASH CID:49 COLOR:RED
 
Model:Z550i
Brand:TIM
MAPP CXC article: R6CA009     prgCXC1250583_GENERIC_ML
MAPP CXC version: R6CA009
Language Package:AMERICA_2
CDA article: CDA102587/40
CDA version: R10A
Default article: cxc1250506
Default version: R6CA009
 
Network LOCKED
Operator: MULTIPLE
 
USERCODE:0000
 
RESTORATION FILE PRESENT FOR DETECTED FIRMWARE
 
Elapsed:14 secs.
Going to execute VKP script....
ChipID:8040,EMP protocol:0301
PHONE IS RED RETAIL PRODUCT
FLASH CID detected:49
Speed:921600
OTP LOCKED:1 CID:49 PAF:1 IMEI:35*********** CERT:RED
PATCH:061204 1529 HAN_DB2010_MEM_PATCHER_R2A007_CXC9876543210 0
LDR:060718 0842 LIE_DB2010_FLASHLOADER_R2A003_CXC1326738
Flash ID check:2019
Flash props sent ok
 
DETACH CABLE FROM PHONE.
REMOVE BATTERY FROM PHONE, THEN INSERT IT BACK
THEN PRESS "READY"
 
Trying to launch embedded bootloader...
INT LDR:COMPACT_ID_LOADER_CRIPPLED_SETOOL2_R2
Flash ID check:2019
Flash props sent ok
FOUND: R6CA009_CXC1250583_GENERIC_ML
Restore from:R6CA009_CXC1250583_GENERIC_ML
Starting to process VKP patch script: D:\Temp\SE\z550i-patch.vkp
VKP script loaded OK. Lines: 6
Patch structure created OK. Determining blocks to read...
New block #0000 added: $44E00000
Blocks selected OK. Reading blocks: 1
Blocks readed to memory OK. Checking contents...
Blocks patched OK. Start writing...
Block 0 written
VKP script executed OK
Elapsed:57 secs.

Does anyone know a way to make this phone work in quad-band mode?

What about debranding and upgrading the firmware to R6GA004? Would it help anything?

Thanks!