A way to downgrade HBOOT from 1.02.0000 to 0.52.0000... May be!
Hi, everyone who have been waiting for a way to downgrade their HBOOT so that they can get S-OFF, cause they upgraded to the Official RUU Rom... I think I found a solution for you!

Also give you permanent ClockWork Recovery!
I haven't test it on any other Slide, cause I have only one. So, sorry if it didn't work for you.
Here is what I did, in case you're wondering, I downloaded the Official RUU from HTC Support website, extracted the 'rom.zip' file from Windows Temp folder that it creates, replaced the newer 1.02 HBOOT with 0.52 HBOOT, that I got from 'ESPRIMG.zip' (the Stock rom).
And also replaced the recovery.img with ClockWork Recovery img file.
Then I just renamed the 'rom.zip' file to 'ESPRIMG.zip'
Put it in the root of my memory card, powered off, rebooted into BOOTLOADER, and it detected the file and asked me if I wanted to update, I chose YES, and it went on without a hitch. Next thing I knew, I had 0.52.0000 HBOOT, with permanent ClockWork Recovery(so I dont have to use 'update.zip' anymore), and also the Official Latest 2.15.531.3 unmodified rom, (I like stock Espresso, that's why I bought it

) but you will
LOSE ROOT but SuperOneClick method works for me to gain root -
http://forum.xda-developers.com/showthread.php?t=803682
Method:
1. Download this 'ESPRIMG.zip' file -
http://www.mediafire.com/file/cuemg7...a3/ESPRIMG.zip
2. copy/paste it to your memory card, in the root, not on any folder.
3. Make sure your card formatted to FAT32 file system, or it won't detect it.
4. Do a Nandroid BACKUP, if you can, cause I don't know if this will work for you. But it will wipe all your data and setting. SO BACKUP!
5. First you need to wipe data and factory setting, and wipe cache and wipe davlik cache (Otherwise it bootlooped for me). So boot into recovery first!
You can do that by going into BOOTLOADER first then selecting Recovery ( for that remove memory card from mobile or else it will start update) or if you have ROM Manager then you can use that to reboot into Recovery, any recovery will do stock or clockwork.
6. Ok, so after Wiping from recovery. PULL battery, then insert back the memory card with ESPRIMG.zip file on it. Reboot into BOOTLOADER, and apply the update.
It should do a reboot automatically to downgrade the HBOOT.
You will see the change if it worked. After applying the update, reboot phone normally.
And if all done correctly, you should have 0.52.0000 HBOOT, and also a permanent ClockWork Recovery. Now you can root by using SuperOneClick method. And also get S-OFF (I didn't need it, cause I have permanent S-OFF!

, at least that's how I explain it)
Im guessing it worked for me because I have a factory unlocked S-OFF HBOOT from HTC. Because, to try this out first, I updated my phone via the OFFICIAL RUU from HTC Support Website and it showed S-OFF on my 1.02.0000 HBOOT.
Then I tried this method and it
did downgrade my HBOOT and I still had S-OFF without doing the AlphaREV method.
So I guess I have a kind of permanent S-OFF??!

:S :?
Hit thanks if it helped.
I am no developer but I am learning

Any feedback would be appreciated.
And yes, my major is CS

and I LOVE IT!
T-Mobile G1
HTC Magic
T-Mobile myTouch 3G Slide
HTC Desire
HTC DESIRE S
HTC Sensation "RIP"
HTC Incredible S ViperVivo 2.5.2, Kernel ZRZ-VIVO-14, 19.00.19_M, S-OFF (Blackrose), 4EXT RECOVERY