Unrooting/Clockwork Mod Complications

[thisiskaz]

Note: the background information to my issue is a bit long, so if you don't want to read it, skip to the bolded text. Just please don't answer my question with, "you have follow the standard steps," (unless that's legitimately the only way) because I already know I can't.

This is a somewhat weird story and a bit complicated to explain correctly. I've been flashing ROMs on my phone for many months now, but a few months ago some problem arose (not sure if it was because flashing a rom or kernel) that either killed my battery or killed some aspect of the internals of my phone. I've never been able to figure out which, although I'm guessing the latter. The basic problem is that if I use data without being connected to a charger, my phone instantly dies. It then uses all or nearly all of its battery life to turn it back on (even if previously at 100%).

The problem was bad but it's progressively gotten worse and worse, to the point that if I text heavily the phone dies. I've been planning on taking it back to Sprint but now that I'm going on vacation I'm definitely doing it. So I start the process of unrooting. I'm able to get S-ON, but when I try to update with img36 or whatever it's called, it started the process and then died in the midst of flashing the radio. Somehow (and honestly much to my chagrin) this does not brick my phone, but now the bootloader appears even more legitimate, except it did not flash the stock rom and clockwork recovery is still an option.

So after trying this for a few times and realizing my phone just won't last, I decided to flash a rooted version of the stock rom. My phone now appears very legitimate, and probably well enough to bullshit the clerks at my sprint store (we don't have one in the area back home that actually does repairs), I still want to be as prepared as possible for my comfort.

In short, I was wondering if there was any way to remove clockwork recovery without flashing that signed img36.zip through the bootloader?