[Nexus One Q&A, Help & Troubleshooting] ksc6000:
This is a lengthy post, but please read it. These are copies of my posts on androidforums.

Post 1:

I happily bought my Nexus One 3 weeks ago from someone on craigslist. I checked out the phone, everything worked, and it's been absolutely great. I'm in the Detroit metro area and have T-mobile. I bought it, rooted it, installed cyanogen's 5.0.5.3 ROM and installed the overclocked-undervolted kernel, and it's been heaven. I'm in love with this phone. Then I drove with my dad to Tupelo, MS, on Sunday the 11th and throughout the drive the signal would disappear and come back, repeatedly. I figured this to be because of T-Mobile's terrible coverage. While in Tupelo, I hardly EVER got a signal...even for calling, forget about data. I knew this would be rectified when I got back to Detroit. Today I flew back to Detroit, and finally got 3G again and full signal and I was ecstatic that I could finally USE my phone again! Well that didn't last, now I'm at home (where I normally only get a GPRS signal), and I'm not getting ANY signal, whereas my sister and mother who are sitting next to me, who are on the same family plan with T-Mobile with me, are getting full GPRS signals on their blackberry phones. I've rebooted the phone multiple times, wiped and re-flashed the cyanogen ROM...no luck. I've even put in my sister's SIM card into the Nexus...still no signal. Meanwhile my sister and mother are getting full signal on their phones, even if its just GPRS. I'm bummed PS > No, the phone is NOT in airplane mode.

Post 2:

I did flash the orignal stock rom, and update the radio (tried 3 different radio images)....none of it helped unfortunately. My Nexus One will work fine when I'm in an area of good signal, namely where I get 3G. But when I'm at home, no dice. And the reason this is really frustrating is because everyone else in my house, on the SAME carrier, with the SAME plan, is getting a full signal. This really sucks because not only is the phone useless as a phone, but the phone runs hot (31 degrees C at idle, instead of 24 C at idle, which it what it always was before), because it's always looking for a signal (and I know this because Call Standby, which used to be 3% of battery use, is now the highest battery drain). And until I left for the trip, this was not a problem at all. So my only conclusion is that while in Tupelo, MS, the antenna/radio fried a bit, constantly looking for a signal for 4 days straight, and so now it can only pick up signals if they're very strong. Either way, I'm gonna have to sell it to someone who wants it for repair parts, and go back to my old blackberry pearl 8100

Post3:

Sent the phone in to HTC.

This is what they told me. I could go two routes: Replacement or Repair. Naturally I'd just want them to send me another certified working phone (refurbished, they don't send new ones). However, with this option, since I wasn't sure if I was under warranty or not (having unlocked the bootloader and rooted the phone, and the customer service guy said they could only determine that once the phone was with them), if they determine that you are NOT under warranty, you will get a replacement, but the cost of any repairs that are needed to the unit you send in, you WILL pay for them, no matter what. If they determined that I am still under warranty and that they can help me free of charge, then obviously this would be the best option. But not knowing if I'd be charged, and how much I'd be charged, I took the repair option.

With the repair option, they give you the option whether you want to authorize the charges once they know how much it will cost (if they can't do it for free). Then you can decide if it's worth the money they're saying, or you can tell them to just send it back, in which case they'll just charge you 28$ for the diagnosis and shipping cost to ship it back. I took this option worried about them telling me that I'd have to pay 300$ or something crazy for the repair if I took the replacement option.

I sent it in on Friday the 16th, and I got a mail from HTC on Monday 10 AM the 19th, telling me they had received the phone. Then at 5 PM I get an email from them saying it's been shipped back. That's it, no other info. I thought, how can they fix it that quick? Or did they mistakenly not even look at it and sent it back with a batch of repaired phones? Or did they just send me a replacement?

I got the phone yesterday the 20th at noon, and opened the package, and it was in fact my phone (it still had the screen protector I'd put on it, albeit they'd completely ruined it, because it had moved and now had all these large air bubbles and dust in it).

I powered it on and the bootloader was locked again, and completely returned to stock. I was at my house at this time, where I've been getting the signal problems (while everyone else at my house, with the same carrier and same plan have been getting full GPRS signal). I pop in my SIM card and YES! It was working, and working well. Made a few calls, walked all around the house, and the calls were clear and strong.

Now at this point, it was a bittersweet feeling, because while my phone was working, I was afraid to root it again. I guess I felt that somehow rooting my phone and intalling Cyanogen's mod 5.0.5.3 must have done it (though I had that ROM on for a while before my trip, when it got messed up). But then I coudln't handle the slower speed, the lack of quicker pulse trackball notifications, wireless tether, titanium backup...and so on. So I rooted my phone, installed cyanogen's mod, downloaded all the apps I had.

Except ONE thing. The only thing I can remember doing before my phone's signal started getting weak was installing an overclocked+undervolted kernel to the phone. I know they say that when your phone is in a weak area, it requires more power to work, so maybe undervolting it is what was doing it, but this doesn't make sense, as I reflashed the cyanogen mod without the kernel, and the stock rom and neither helped. Wouldn't they overwrite the kernel with the kernel's in the ROMs? Either way, that was the last thing I did to my phone before it started messing up, so while I put on every app (including setcpu) back on my phone, I didn't put the kernel on it.

So far so good, it's been a whole day, and it's worked fine at my house. All I can say is I'm enjoying my phone again. Thanks to all of you, and I hope this thread helps out someone else in a similar predicament.

Now that my phone is working fine, and the only thing I have not put back on my phone is the undervolted+overclocked kernel, I'm wondering if that's what ruined my reception at home, which is a weak signal area.

The thing that confuses me is that I thought when you flash a ROM, it over-writes the kernel with its own, but even though I flashed the stock and cyan's ROMs after full wipes, it didn't fix the problem, so I'm assuming that kernels don't get over written?

Since you guys are the experts, what do you think happened to my phone?

I am now afraid to even TRY to do anything to the phone. I really wanna try out Modaco's desire rom to try out sense UI, but I feel like I'll just risk my phone's reception again.