Stuck in bootloader topic

Hello everyone,

This is my very first post here but I'm following a lot of topics here. I'm French so excuse me for my poor English ;)

Okay I've got a big problem with my HTC One. I wanted to unroot the device by relocking the bootloader and turning in S-ON. Which I managed to do (even if it was written Relocked instead of Locked but anyway ...). Thing is that I'm now stuck in bootloader and I can't install any custom ROM. I can go to the recovery but I don't have ROM file in it.

I try to do the adb commands on my PC but I've got error messages like these :

C:\fastboot>adb shell
error: device not found

or

C:\fastboot>adb start-server
* daemon not running. starting it now on port 5037 *
* daemon started successfully *

Can I use ADB while in bootloader ? Fastboot seems to be ok (it recognizes my device) but I really need to install a ROM on my device if I want it to reboot.

I'm really stuck and my phone is useless now.

More information :

***TAMPERED***
***UNLOCKED***
M7_UL PVT SHIP S-ON RH
HBOOT-1.54.0000

I hope you'll be able to help me.

Thank you very much,