Here is what Sony had to say
Status: Analyst Andrew_ is here and your issue status is: working Problem: My TV suffers from uneaven cloudy backlight and I have tried the suggested settings but even tho is has substantualy darkened my picture the clouds are still there. I have read about a software update available from sony but i fear it will make my picture End Session user paul has entered room
analyst Andrew_ has entered room
Andrew_> Hi Paul. Welcome to Sony Online Support. I am Andrew. Please allow me a moment to review your concern.
Andrew_> Thanks for waiting, Paul. I'm sorry that the TV is not working normally. I'll be glad to assist you with this.
Andrew_> Could you please let me know the other devices that are connected to the TV?
paul> digital cable high definition box
paul> I would like to know more about the software update from sony available mid febuary
Andrew_> Please make sure that the connections are correct and secure with the TV.
paul> It doesn't msatter what input is used the backlight is the problem
paul> it shows on all setting and all inputs
Andrew_> I would like to forward a link to a page where you can view the information to resolve the issue.
Andrew_> When you receive the link please click on it to open the page and let me know if you are able to view it.
paul> I have already veiwed it and I would like to know more about the software update that will be provided
Andrew_> Please perform the steps that are given on that page and check if it works normally.
Andrew_> Currently, there are no software updates available for the TV.
paul> yes i veiwed this page and tried these steps and it does not fix the mura defect i told you about
Andrew_> I suggest that you reset the TV and check if it works normally.
Andrew_> To Reset the TV, disconnect the power cord for a short period of time (approximately 1 minute), then reconnect the power cord and power on the television.
paul> the support site speaks of a software update that will be available mid febuary please tell me more about it . I tried the power cord and it did not work turning off the power for 1 minute then turning the tv back on
paul> can you please tell me more about the software update that will be available from sony mid febuary that i read about on your support site
Andrew_> We do not have any information on the software.
paul> It is on the web site can you please tell me more
Andrew_> We really do not have any information on the software. Currently, there are no software updates available for the TV.
paul> Do you need the link to veiw the support site ?
paul> Are you aware that the support site offers a software update for mid febuary?
Andrew_> I'm sorry, we do not have any information on the software.
paul> If it is posted on the sony website some one from sony must be aware of the software update that can be sent to me be usb dongle who can tell me about this
Andrew_> We do not have any information on the software
paul> are you aware of it being offered on the support site?
here is the link
Andrew_> Once, the software is updated, it will be posted online.
Andrew_> The link that you have sent to me is for another TV.
Andrew_> The KDL46V2500 TV does not have any software update.
paul> can software repair a hardware defect or is the mura defect purely a software defect if it can be fixed by a software update?
paul> hello are you there?
Andrew_> Yes, I'm online.
Andrew_> the software update may repair hardware defect but we do not have any information on this.
paul> Thank you for your time Andrew.
Andrew_> You're welcome.
Andrew_> Thank you for contacting Sony online support today. We wish you a happy holiday season.
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BTW I almost fell of my chair when I saw that tv on that boat omg.