So folks are now posting all manner of issues on this thread, but to my mind, based on the original issue here, this thread is about the impact to iPhone 4 series users from upgrading to iOS 6.1.3 leading to greyed out wifi button, and/or inability to scan for and connect to wifi networks and similar Bluetooth issues.
I had posted essentially my disappointment with Apple for failing to acknowledge the issue and give those experiencing it at the very least some peace of mind that they have a legitimate issue and a solution I on the way. This has shaken my confidence in the firm in relation to basic principles of commercial integrity and its responsibilities to its user base. In the meantime people are incurring costs paying for service and replacements and wasting time searching for solutions. It's a poor show Apple.
The other thing I wanted to report here is that 1 solution does appear to have worked for me. The practice of putting your phone in a ziplock bag & then in the freezer for 30 mins has been roundly ridiculed in some quarters on this thread. I tried it however out of desperation and I can report that after having extremely intermittent and short lived access to my home wifi, I now have a fairly consistent connection. It drops occasionally, but recovers within a few seconds. The device is now usable again.
I know that there's little foundation in the public domain currently as to why this process would work at all, but it did for me. I dropped into airplane mode, then switched it off, then put it in a bag to prevent condensation then in the freezer for 30 mins. When I took it out the bat was flat. I left it for a further 30 mins to return to room temperature, then recharged.
On booting up, and disengaging airplane mode, I was able to see not only my network, but those of my neighbours also (which had previously not been visible)
It's risky no doubt, particularly if like me you're out of warranty. Each will have to make their own call as to whether to entertain this seemingly superstitious and charm-like approach to restoring functionality. I wish you all the best as I know how frustrating this issue is when it's in effect.
And again I say to Apple, step up, do the right thing and be transparent about what's going on here. We get that there will always be ticks and bugs along the way with leading edge hardware and software. However the goodwill of your users us running out on this one.