No help, but i've never had that issue, not once. I lose signal quite a few times too living in the sticks.

 

You could have a faulty SIM. Had one my self a few yaers back doing as you describe.

 

This happened to me today for the first time. But it automatically went to airplane mode and when I turned it off it came up with the no sim card detected notification. A reboot fixed it, however I did not have to wait 5 mins as you did. I am pretty sure it is not a sim card problem since it was from my old phone which never had similar problems. I currently have the HTC desire with Android 2.1. No idea what caused it though.

 

OK, not sure if this is the fix ... but it seems to have fixed mine. I turned the sim lock to off, so there is no pin needed to unlock. I think there was a problem where it could not unlock the sim.

 

Glad you got it sorted.

 

I have the same problem. I tryed to change sims and it was same problem, too... So now i`m wondering if tis sim card or the phone...

 

Had the same with mine today. As it was out of warranty i took it apart to have a look.
As it turns out it is an issue with the design of the simcard reader as far as I can tell. At the back if it there isnt anything stopping the sim card from hitting the battery and going in to far (or at least there wasnt on mine).
After i realized this I put my sim card back in, ensuring that I didnt push it right the way back, It now works.
As far as i can tell there is a little bit of resistance when its in far enough but pushing it to much pushes it past where the reader can read it.
Hope this helps

 

One of many problems i have encountered with my HD, failed GPS antenna, sent back to HTC for repair, random changes in app settings, ringtones and of course signal dropping out accompanied by the re-starting no sim card message. Im currently with Vodaplank, my wife has the HD with Treemobile works fine, no issues, put our phones together activate GPS hers locates within 3 seconds mine takes up to 30 seconds. Take my sim card out and put it in her phone works first time every time. I think i have a LEMON but i also think the network adaptive software has something to do with it, maybe. What i do know is HTC wont be my first choice at upgrade time and after 10 years with Vodaplank unless they can offer me something truly irresistible neither will they.

 

I love you, Codeccarus, it worked!! thanks a lot for this great tip! ))

 

I tried several times removing and reinserting the SIM card and still had a problem...took the phone to a store and sales person tried the card in another phone and it worked fine...he said it's my phone. I removed the card one more time and blew forcefully into the slot several times and put the card back in. Success! Must have been dust in the slot.