[Xperia Arc Q&A, Help & Troubleshooting] nosxman:
Hi everyone, thanks for reading this, and I hope you would have some answers or solutions for my problems

here is my phone's specs

the back of the phone

i look up my imei on numberingplans

aboutphone

software info

configuration

emma

1. from specs i reckoned my phone's bootloader is locked, but when i try to unlock , it said the phone was already unlocked what's wrong?

2. I am able to boot into recovery using this method and has successfully rooted the phone

3. I can not upgrade to 4.1.B.0.587 using PC Companion or Update Service. Every time I try it halts, the phone gets into boot loop but i can fix it by flashing Xperia 2011 Range_FreeXperia_ALL.ftf, OTA informs me there is no update

5. flashtool doesn't work when i try to flash any stock roms it always come with this error, usb debug on, unknown source on, msc mod on

12/009/2013 02:09:19 - INFO - <- This level is successfully initialized
12/009/2013 02:09:19 - INFO - Flashtool Version 0.6.9.1 built on 2012-04-09 19:22:19
12/009/2013 02:09:19 - INFO - You can drag and drop ftf files here to start flashing them
12/009/2013 02:09:25 - INFO - Device disconnected
12/009/2013 02:09:35 - INFO - Device connected with USB debugging off
12/009/2013 02:09:35 - INFO - For 2011 devices line, be sure you are not in MTP mode
12/009/2013 02:09:35 - INFO - Device connected with USB debugging on
12/009/2013 02:09:39 - INFO - Connected device : LT18
12/009/2013 02:09:39 - INFO - Installed version of busybox : N/A
12/009/2013 02:09:39 - INFO - Android version : 2.3.4 / kernel version : 2.6.32.9-perf
12/009/2013 02:09:54 - INFO - Root Access Allowed
12/010/2013 02:10:20 - INFO - Device disconnected
12/011/2013 02:11:25 - INFO - Selected LT18i_4.1.B.0.587_Generic_Global.ftf
12/011/2013 02:11:25 - INFO - Preparing files for flashing
12/011/2013 02:11:51 - INFO - Please connect your device into flashmode.
12/012/2013 02:12:00 - INFO - Device connected in flash mode
12/012/2013 02:12:00 - INFO - Opening device for R/W
12/012/2013 02:12:00 - INFO - Reading device information
12/012/2013 02:12:01 - INFO - Phone ready for flashmode operations.
12/012/2013 02:12:01 - INFO - Start Flashing
12/012/2013 02:12:01 - INFO - Flashing loader
12/012/2013 02:12:03 - INFO - Loader : S1_Loader_Root_773f - Version : R4A066 / Bootloader status : ROOTED
12/012/2013 02:12:03 - INFO - Flashing adsp.sin
12/012/2013 02:12:03 - INFO - Ending flash session
12/012/2013 02:12:03 - [COLOR="Red"]ERROR - ERR_SEVERITY="MAJOR";ERR_CLASS="SECURITY_CLASS";ERR_STATIC="SIN_HEAD_VER";ERR_DYNAMIC="Failed to verify sin header"; [/COLOR]
12/012/2013 02:12:03 - ERROR - Error flashing. Aborted
12/012/2013 02:12:03 - INFO - Device connected in flash mode
12/012/2013 02:12:05 - INFO - Device disconnected
12/012/2013 02:12:07 - INFO - Device connected in flash mode
12/012/2013 02:12:47 - INFO - Device disconnected
12/013/2013 02:13:04 - INFO - Device connected with USB debugging off
12/013/2013 02:13:04 - INFO - For 2011 devices line, be sure you are not in MTP mode

i try all the flashtool version i can find, but it doesn't work,

i really want to update stock 4.1.B.0.587, unlock boot loader, and root

i can go to a sony service centre to update to 587 but then i can not root it because when i try to flash the required kernel, it always the error Failed to verify sin header flash tool doesn't work for me

the sony service center won't root for me :(