I'm hoping someone can help me here... I have an S3, purchased from Warehouse Stationery on 2 degrees  when they first came out. The February 2013 update pushed from the Samsung push service killed it, and now Samsung are declining warranty stating:
DEFECT : error message when booting the phone Firmware update failed, phone wit
REPAIR : SW tampered, warranty declined. quote to replace MAIN PBA

Now I'm not technical at all when it comes to Android, but the most custom thing I (or anyone else, other than a Samsung technician?) have ever done to 'tamper' my phone is to replace the 2 degrees sim with a Telecom sim when I purchased it, and install apps from the Play store, neither of which would strike me as warranty-voiding events; so either someone at Samsung is lying to me or something strange is happening here. I assume what they're trying to tell me it that I've rooted my phone, which really irks me as I haven't seen any need to, wouldn't know how to, haven't had anyone offering to, and wouldn't dare to  as I knew it would void the warranty (and I'm pretty sure you can't root a phone subconsciously). So here's the stats, and hopefully someone can make sense of it all:

The Screenshot that Samsung sent back to me as as evidence had the following:
ODIN MODE
PRODUCT NAME: GT-I9300
CUSTOM BINARY DOWNLOAD: Yes (1 counts)
CURRENT BINARY: Custom
SYSTEM STATUS: Official

Does this mean that they are trying to say that I've rooted my phone?

The sequence of events that led to the phone's demise is as follows: 

1. This Phone was purchased originally from Warehouse Stationary in July 2012.The OS at that stage was Ice cream Sandwich. It came with a 2 degrees sim. I replaced this with my telecom sim.
2. The closest I’ve come to customisation since then is installing software off the Play store. None of these has ever said anything about requiring a root.
   
   
3. At sometime late in 2012, the Samsung push service pushed out an update advice that I accepted (even though the push service doesn’t tell you before accepting just what the update is). It turned out to be the update to Jelly Bean, which all worked fine  and has continued to work fine for months.
4. Sometime early in the week 9 Feb to 17 Feb, the Samsung push service notified me of another update that it wanted to install (again, some info on the screen as to what the update is would be nice). Since I was on holiday that week and not on WiFi, I chose the “Postpone” option.
5. Later that week, while still on holiday, I got the reminder. The Postpone option wasn’t available the second time, so I clicked the Cancel option (I can’t remember if the word was “cancel”, ‘decline” or whatever, but you get the drift).
6. I arrived back home and decided that now I could get that upgrade since I was back on my home WiFi. So I went from the home screen to Settings > About Device > Software Update > Update, from which it gave me the options to Cancel, Wifi settings, or OK.  But then I realised I was out of time and needed to get in to the office, so I clicked “Cancel” (since I was about to drive away from my home WiFi.
7. I did not look at my phone again until I returned to the office. When I pulled out the phone, I was sitting on a message, I can’t remember the wording, but something about security encryption code failed to update or something like that. So, I powered my phone off, hoping just a power off and on again would make things all happy again. This was not to be. I can’t quite remember whether it successfully powered off at that point or whether I had to remove the battery.
8. From that point on, every time I powered it on, it would just get as far as the Samsung GT-I9300 splash screen and hang there.
9. Now I gave it to our network engineers, who attempted to do an emergency firmware restore using Samsung Kies. The “downloading” progress bar moved to 100%, but then the installing progress bar remained at 0%. They attempted this several times with the same result.
10. It was at this point that the phone was brought into the Warehouse Stationery store for warranty.

What I've read since Samsung's response indicates two major issues with the S3, one being SDS, and the other being the root exploit flaw  found here: http://forum.xda-developers.com/showthread.php?p=35469999
This doesn't look to me like a case of SDS because the product name still shows.
Is it possible that this security flaw may have been exploited on my phone by a download from the App store? Does such an exploit have a signature which would be in keeping with the ODIN MODE above?

What I'm confused mostly about is, if my phone had been rooted, how would I have still being receiving updates from the Samsung Push Service? I thought you didn't receive updates from the Push service on rooted phones? I note that the root security flaw "Obtains root without ODIN flashing" (I had a friend check this before I took it into the store and it wasn't flashing, but that meant nothing to me at the time), and that Samsung's screenshot still says "SYSTEM STATUS: Official". Does this mean that this security flaw could have customised my phone such that the Samsung Push Service didn't know it was customised, and therefore pushed out the update, which failed because of same customisation? Or is there another explanation for all of this? Either way, I'm feeling fairly shafted by Samsung right now, and my complaint to their Customer Care (sic) centre is going nowhere fast. Any help appreciated!