Software downgrade - warranty void?

[MattC2]

Just had to call to book my phone in for repair.  It's started doing the whole not recognising charger BS again and I really don't have the patience anymore to mess around for days to get it to work for just a week.  Bit concerned however as I told guy on the phone I downgraded back to ICS as it allows me to charge there and he told me that will have voided my warranty by doing this?  I told him I haven't unlocked bootloader or anything like that and he said it's still modified so if they can tell this they will not repair it.  Anyone else had this?

[FrontierGate]

Downgrade with Sony stock ICS firmware?

Check this thread:

http://talk.sonymobile.com/t5/Xperia-S-SL-acro-S/Will-Flashing-Firmware-From-other-region-Void-Phone...

[_alexdon_]

This is up to your local xperia care,each has their own rules.Some say even downgrading with official ftf from Sony will void warranty.

[wobba-lee]

As long as the customisation number on the software you flashed matches that labelled physically on the device then you will be fine they wont be able to tell. 

If they get a device with non matching software to device they will throw it back at you with a big bill. Just make sure they recieve the device with the correct software on and they will be none the wiser.