[XPERIA X10 Q&A, Help & Troubleshooting] Roger00:
Yeah I can flash ftf only, the phone is recognised in flash mode only.

Here's a log from just now:

25/046/2012 23:46:10 - INFO - Device disconnected

25/048/2012 23:48:31 - INFO - Selected X10i_3.0.1.G.0.75_CUST-UK GENERIC 1235-7379.ftf

25/048/2012 23:48:31 - INFO - Preparing files for flashing

25/049/2012 23:49:07 - INFO - Please connect your device into flashmode.

25/049/2012 23:49:17 - INFO - Device connected in flash mode

25/049/2012 23:49:17 - INFO - Opening device for R/W

25/049/2012 23:49:17 - INFO - Reading device information

25/049/2012 23:49:17 - INFO - Phone reading for flashing.

25/049/2012 23:49:17 - INFO - Start Flashing

25/049/2012 23:49:17 - INFO - Flashing loader

25/049/2012 23:49:21 - INFO - Loader version : R4A024 / Bootloader status : UNROOTABLE

25/049/2012 23:49:21 - INFO - Flashing kernel.sin

25/049/2012 23:49:23 - INFO - Flashing dsp1.sin

25/049/2012 23:49:30 - INFO - Flashing fota1.sin

25/049/2012 23:49:32 - INFO - Flashing fota0.sin

25/049/2012 23:49:33 - INFO - Flashing amss.sin

25/049/2012 23:49:34 - ERROR -

25/049/2012 23:49:34 - ERROR - Error flashing. Aborted

25/049/2012 23:49:34 - INFO - Device connected in flash mode

Here's another with a different ftf file:

25/050/2012 23:50:19 - INFO - <- This level is successfully initialized

25/050/2012 23:50:19 - INFO - Flashtool Version 0.6.7.0 built on 2012-01-21 17:31:40

25/050/2012 23:50:19 - INFO - You can drag and drop ftf files here to start flashing them

25/050/2012 23:50:20 - INFO - Device disconnected

25/051/2012 23:51:09 - INFO - Selected X10i_2.1.71_ARO.ftf

25/051/2012 23:51:09 - INFO - Preparing files for flashing

25/051/2012 23:51:12 - INFO - Please connect your device into flashmode.

25/051/2012 23:51:22 - INFO - Device connected in flash mode

25/051/2012 23:51:22 - INFO - Opening device for R/W

25/051/2012 23:51:22 - INFO - Reading device information

25/051/2012 23:51:22 - INFO - Phone reading for flashing.

25/051/2012 23:51:22 - INFO - Start Flashing

25/051/2012 23:51:22 - INFO - Flashing loader

25/051/2012 23:51:26 - INFO - Loader version : R4A024 / Bootloader status : UNROOTABLE

25/051/2012 23:51:26 - INFO - Flashing amss_fs.sin

25/051/2012 23:51:26 - INFO - Flashing cache.sin

25/051/2012 23:51:27 - INFO - Flashing fota1.sin

25/051/2012 23:51:28 - INFO - Flashing dsp1.sin

25/051/2012 23:51:32 - ERROR -

25/051/2012 23:51:32 - ERROR - Error flashing. Aborted

25/051/2012 23:51:32 - INFO - Device connected in flash mode

I'm totally baffled at this stage lol

I ran the s1 tool with the phone in Flash Mode:

Welcome to S1 tool.

TO CONNECT NEXT PHONES

X10 Xperia,E10 Xperia Mini,E15 Xperia X8,U20 Xperia Mini Pro

LT15 Xperia ARC,MT15 Xperia NEO,R800 Xperia PLAY

PRESS AND HOLD "BACK" BUTTON...

PLEASE ATTACH TURNED OFF PHONE NOW

RUNNING S1_EROM VER "R8A013"

SOFTWARE AID: 0001

LOADER AID: 0001

FLASH ID: "002C/00B3"

LOADER VERSION: "R4A024"

MODEL (from GDFS): X10i

SOFTWARE VERSION: 1241-6324_2.1.A.0.435

CUSTOM VERSION: 1234-4579_R15B

FILESYSTEM VERSION: VFE-1-4-8_2.1.A.0.435

SERIAL NO: CB511H8XKK

SEMC SIMLOCK CERTIFICATE

Elapsed:19 secs.

You see the phone was like this when I got it, the guy said he tried to update and this happened to it, so I don't even know if debugging and Unknown sources is ticked or not, cosmetically the phone is in as new condition.