[Xperia Arc Q&A, Help & Troubleshooting] Phenomzye:
Hello, I'm new here, bought my Xperia Arc S rooted with 4.0.4 and .587 kernel, xda has helped me a lot but unfortunately I haven't been able to install Jelly Bean, no matter how hard I try... so, basically my problem is

After lots of failed tries to install JB, I ended up with a bricked phone, so I had to flash an official .ftf with its kernel, all okay. Now the bad thins is, I lost my root, and the phone came rooted so I have no idea how to do this, I've followed these steps:

-Install ADB drivers

-Flash/Downgrade kernel

-Debug mode checked

-Unknown sources checked.

then, when I try to do the root, this is what happens (this is the log of cmd).

---------------------------------------------------------------
Easy rooting toolkit (v4.0)
created by DooMLoRD
using exploit zergRush (Revolutionary Team)
Credits go to all those involved in making this possible!
---------------------------------------------------------------
[*] This script will:
(1) root ur device using latest zergRush exploit (21 Nov)
(2) install Busybox (1.18.4)
(3) install SU files (binary: 3.0.3 and apk: 3.0.6)
(4) some checks for free space, tmp directory
(will remove Google Maps if required)
[*] Before u begin:
(1) make sure u have installed adb drivers for ur device
(2) enable "USB DEBUGGING"
from (Menu\Settings\Applications\Development)
(3) enable "UNKNOWN SOURCES"
from (Menu\Settings\Applications)
(4) [OPTIONAL] increase screen timeout to 10 minutes
(5) connect USB cable to PHONE and then connect to PC
(6) skip "PC Companion Software" prompt on device
---------------------------------------------------------------
CONFIRM ALL THE ABOVE THEN
Press any key to continue . . .
--- STARTING ----
--- WAITING FOR DEVICE
error: more than one device and emulator
--- creating temporary directory
error: more than one device and emulator
--- cleaning
error: more than one device and emulator
--- pushing zergRush
error: more than one device and emulator
--- correcting permissions
error: more than one device and emulator
--- executing zergRush
error: device offline
--- WAITING FOR DEVICE TO RECONNECT
if it gets stuck over here for a long time then try:
disconnect usb cable and reconnect it
toggle "USB DEBUGGING" (first disable it then enable it)
error: more than one device and emulator
--- DEVICE FOUND
--- pushing busybox
error: device not found
--- correcting permissions
error: device not found
--- remounting /system
error: device not found
--- checking free space on /system
error: device offline
error: device not found
error: device not found
--- copying busybox to /system/xbin/
error: device not found
--- correcting ownership
error: device not found
--- correcting permissions
error: device not found
--- installing busybox
error: device not found
error: device not found
--- pushing SU binary
error: device not found
--- correcting ownership
error: device not found
--- correcting permissions
error: device not found
--- correcting symlinks
error: device not found
error: device not found
--- pushing Superuser app
error: device not found
--- cleaning
error: device not found
--- rebooting
error: device not found
ALL DONE!!!
Press any key to continue . . .

of course, that "ALL DONE!" is a lie and useless, and I'm still unrooted, no reboots, anything. I hope you guys can help!

My phone has unlocked bootloader, it's a SonyEricsson Xperia Arc S Lt18i with ICS 4.0.4 and kernel 4.1.B.0.587

Thanks in advance ^w^