[HTC Incredible S] John Anderton:
Cause of the Security Warning issue and it's solution

I'm sure someone already said all this shiz but I'll say it anyway. I had this problem too. Here's what happened, why it happened, how to avoid it and how to fix it.

What happened:

I tried going from a custom ROM back to stock and got stuck half way with no OS, a badly screwed up bootloader which refused to do anything

Why it happened:

Because I tried installing a ROM with a lower mainver than I was on.

Why in the world did I do that? Because I didn't know my mainver was lower. I tried installing a ROM I had used before. The problem was, flashing a radio had upped my mainver because the file had a txt file with a higher mainver that the OP of the thread didn't fixed despite being asked to multiple times by people.

Why am I getting this message?

In my case, I was S-Off and on a custom ROM and unknown to me, I had a higher mainver than the stock RUU I was going to install. It removed all my data and installed it's boot loader and other rather useless things first leaving all the juicy stuff (OS/radio) in for later. Now when it tries to install the important stuff, it realizes that the mainver check is failing. BAM.. it aborts. Bad for you, eh? :P There is a better reasoning as to why this happens which kmdm/ief told me about on IRC but I can't find it in my logs.. it's been well over 2 months since this hapened to me :)

How to avoid it:

1) Don't go back to stock :P

2) If you want to, check your mainver first

3) If your mainver > mainver of RUU you're trying to install then don't install it

4) If you still want to install the same RUU, get an installer like a radio, rename it to PG32IMG.zip and before you flash it, open it up, check the txt file in it, change the mainver to something lower, put it back in the zip, confirm if the txt file got updated then flash it on your phone. This SHOULD reduce your mainver. I haven't tried it yet but in theory, it should work because you're S-Off. You can't do this when you're in security warning mode because your bootloader is S-On and your phone will not install anything that isn't signed and this bootloader has a check against downgrading :)

How to fix it:

Get a RUU with mainver >= your current mainver.

How do you check what your current mainver is? I think you can check with fastboot getvar all

If you weren't S-On, you could just flash a file (like I said above) and lower your mainver but that's not the case here. You are probably S-On now and can't install any any unsigned code. Your only option is to install the RUU again.. and it has to be one with a mainver >= your current mainver.

For me, when I took the exe, got rom.zip, renamed it to PG32IMG.zip and tried to flash it when I was in a security ****ed up mode, it read the file and did nothing.

Try it out and hope it works.

If that doesn't work, your second option is to flash it via fastboot. Run the following commands

That failed a signature check on me once. Did it after 2 days and it worked.. Not sure if it was the reboot of my PC.. probably was. But people told me it was that I wasn't in RUU mode properly which I disagree with..

If your sig check fails, make sure your file is not corrupt during download (hash check would be great :)). Else try to get into the RUU mode after a phone reboot a couple of times. Last option, try to restart your machine and make sure your drivers and all are sorted out (no other application trying to interrupt)

If you get a message like "FAILED (remote: 90 hboot pre-update! please flush image again immediately)", try again! Will work the next time.. did for me :)

Hope this helps. And for future reference, please make sure you read this post of mine :)

After all of this is done, head on over to http://revolutionary.io and download their latest version. Get S-Off + root once more just like you once did with AlphaRevX and enjoy your stock OS knowing you can always have the power to do what you please with your phone :)

How do I reduce my mainver?

Read http://xdaforums.com/showpost.php?p=16777575&postcount=43