[Sony Xperia S, Acro S, Ion] :
(Your phone will respond & should respond to fastboot and flashmode only when charge is more then factory charging (50%) or allows flashes in between charging cycles)

Ok Now I Understand Your Problem,

Assuming you know the basics of flashing STOCK ROM via Flashtool

Do Not HARD RESET 3 Vibrations. Recovering From This Deep Level Of Soft Brick Is Very Hard, Takes Lots Of Time.

First of All, Please Connect Your Phone To The Wall Charger. Untill it Turns Green. This will Take a Long Time.

You can Work On Your Phone i.e Flashing And Stuff only When it is charged enough for working conditions.

On a working phone there are different stages of a battery's charging cycle. The stages are listed in order they happen. The cycle goes from a completely dead battery through a phone running on battery and back to a completely dead battery.

Dead battery. No response from the power button, no screen and no led.

Connect to charger

Low battery level charging mode. This is when just the RED led is on and no screen. At this stage the battery's charge is to low to turn the phone on, but it is charging.

Kernel controlled off-line charging mode. This is when the battery has charged enough from step (3) and

boots the kernel

to charge the battery. The phone is off, but could be turned on using the power button. A quick press of the power button will show this battery icon. Icon will fill with charge.

The kernel also controls charging when the phone is on.

Battery is fully charged. Green LED. You Can Start To Recover Your Phone.

Unplug the phone and turn on.

Battery is dead from normal use.

Repeat stages starting at (1)

If your phone is not working but you see a led or have bootloops DO NOT USE HARD-RESET. This can make your phone lock/freeze up until the battery dies. It can take as much as 60hours to die.​

How to Recover?

First Calm Down And Understand The Next Few Point. [MENTION=4859609]ronex1234[/MENTION]

The memory chips need lose power to clear the bad data and reset the phone. Either by the battery going dead or by unplugging the battery.

You can to leave the phone on a charger to see when the battery dies. Usually the battery will not charge in a soft-brick state and will die while still plugged in. After the reset you should then get the red led. However if you get a red led immediately when first plugged in and no response but red led for a long time, then you may need to leave the phone unplugged and let the battery die.

Only after the chips reset will you get the red led. The RED LED should mean the phone is charging in 'low battery level charge mode'.

Once you get the red led, after the reset, do NOT try to turn on the phone. If you try to start the phone now without fixing the problem you will have to start all over.

This is what you need to do, Read Carefully.

keep charging with wall charger. A charger has a higher current rate and should charge faster than a PC.

Make flashtool ready to flash your stock.ftf file. If you are experiencing errors while flashing the entire ROM try to flash just the kernel, check off all in the exclude box except kernel. At this point your battery is very low and doing this will make the flash process much faster than trying to flash the entire ROM.

Try to connect phone in flash-mode. If your phone has enough battery you will get green led. If the flash fails on the first try, just put it back on the charger and wait about 10-30 minutes and repeat. It may take a while to charge enough to flash.

If you see the red led go out, then try for flash-mode.

If you get bootloops, try to flash between loops. As soon as you notice loop, hold volume down and plug the phone into PC with FlashTool ready. Once the loop starts you have very little time to flash, before the loops drain the battery. If you can not flash, the battery will have to die and phone reset. Then start over with red led.

After you complete the flash, unplug the phone and see what happens. Sometimes it will boot to Sony screen and then shut off by itself, if so plug in to a charger. You should get the red led then the battery charging screen then. After about 20 minutes of red led.

If you get a green led (for flash mode) then press the power button until 1 vibration. The green led should flash 1 time. This will end flashmode and start the phone. If you don't end flashmode the phone will still give a green led whenever plugged in, but it will not charge, until the battery dies and the phone resets again.

If you were able to flash the entire stock.ftf file and your phone has gone from red led to the charging screen, then your phone should now be recovered and turn on normally.

If you could only flash the kernel then you will get bootloops. Again you can unplug and try a hard-reset to turn off the phone. If hard-reset works plug in charger and wait for red led and then charging screen.

If you don't do a hard-reset, the phone boot looping should kill the battery and then plug in charger (this is what I did). Then wait for red led and then charging screen.

Now you should have a good kernel and the phone plugged in. You should have the charging screen with the battery icon and led for 'off-line charge mode'. Charge until over 50%. A quick press of the power button will bring up the charging screen.

Once over 50% then flash the full stock.ftf with a full wipe.

If you got this far but still cannot flash a full stock.ftf file then try to use PC Companion software to REPAIR your phone. Make sure battery is more than 50%.

If all fails then post a copy of the FlashTool log in this thread.

Thank You [MENTION=3506348]ToledoJab[/MENTION] For his Amazing Guide [Here]