[Xperia Arc Q&A, Help & Troubleshooting] vashta:
For Arc (LT15i ) // Unlocked Bootloader

Step by Step Flashing a Custom Rom, from Stock /w auto rooting

For Arc (lt15i) // Unlocked BL

| For locked bootloader, try this : Tesla's Guide

You can use this guide, on any custom rom.

I'm using Ultimate HD 3.0.2 when build this guide.

For who kinda new of using flashtool or installing / flashing and rooting a rom.

*note for autorooting : The term 'autorooting' i used here mean that your device will automatically rooted, so you don't have to use the root tool/guide again to have root. This is because the cusrom i used on this guide (uhd 3.0.2) is pre-rooted . Which mean, u only just install the cutom kernel, than ur deviced is rooted.

Preparation

. Copy your custom rom.zip to your sd card ( ex: UHD 3.0.2.zip )

. Copy your custom kernel wifi modules.zip to your sd card ( ex: modules.zip )

*you can get the modules, from the custom kernel thread you use

*some kernel ex: Lupus v11 up , doesn't need separate modules zip, as it's integrate (inside) with the kernel

. I'm using Flashtool 0.9.9.0 *be aware that some user have problems bootloop with different version

. Download recommended base rom (ICS) => LT18i_4.1.B.0.587_(1254-2716).zip : dev-host

*It's stock firmware of 4.1.B.0.587 for Arc S, i used it to increase system partition memory from 380mb to 420mb.

*It's very recommended to use this firmware, if you're gonna using UHD 3.02, coz the rom need a lot of space in system partition, and lot of arc user have problems installing the rom if using LT15i firmware.

A. Back to official rom (unrooted).

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. Open flashtool, then click flash button (lighting icon). Choose Flashmode then ok.

. Select LT18i_4.1.B.0.587_(1254-2716) // wipe data , cache, apps log is checked // All exclude, unchecked // No final verification checked then click ok

. After a notification to plugin ur device pop up, connect ur phone (with power is off) while pressing the back key

(it's the left one, not the right one.. the picture on the flashtool is using different device).

. If ur doing right, the led phone will turn green and it will automatically flashing the phone

. After finish 100%, unplugged ur phone.

. Don't turn on the phone yet... let straight to step B

B. Install custom kernel

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. With phone still power off, connect ur phone to pc, but with holding the menu key now (the right one).

. If ur doing right, the led phone will turn blue and in the flashtool screen you will see that ur phone is in fastboot mode ( this is the mode u will often use if u wanna change different custom kernel).

. Click flash button (lighting icon). Choose fastboot then ok. A menu will pop up, choose 'Select kernel to Flash'

. Open ur desire custom kernel (file with this extension -> *.elf / *.img / *.sin ).

. It will automatically install after u choose to open it.

. Close it after finish

note :

. Choose kernel that have recovery mode on it. ex: CWM (Clockwork Mod) or TWRP. (Mostly user is familiar with CWM)

. In my case, i'm using Vengeance [ARC/S/PRO][1.32] kernel now. I choose Anzu, because my device is Arc. Also don't forget to download modules.zip, it's for wifi.

. There are many good kernel available for arc/s user like Lupus, Rush, Adv. Stock Kernel, etc, choose what suit for you

C. Install custom rom

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. Turn on ur phone now then keep pressing volume down to enter CWM.

. Standard operation before installing new rom :

- wipe data/factory reset

- wipe cache partition

- mount and storage -> format /system

- advanced -> wipe dalvik cache

- advanced -> wipe battery stats

. Now install zip from sdcard -> choose the UHD zip file, and follow the instruction in aroma. After finish don't reboot yet.

. Unchecked the reboot in aroma, after finish, u will be back in cwm.

. Now install the wifi modules first ( usually the custom kernel have their own wifi modules).

. reboot system.

. Finish

. Do the steps above, and u will not having bootloop.

. No need to thinking about rooting, Ur device is already root now because mostly cusrom and cus-kernel now is pre-rooted.

. After succesfully installing the UHD 3.02 Rom.. Better to check this Link : [SHARE] Collection some UHD 3.0.2 known problems n link solution / flashable.zip(CWM)

. Personally I usually never goes to step 1. Just because stuck on sony logo, i'm doing that just once :D

This is just for beginner who want to clean wipe, and face a hardtime because stuck / bootloop.

For me, just having stuck on sony logo, or other stuff, I'm just doing from step 3. Back again to cwm, and installed over...