Yes but you can't get WUP installer to work unless you can get into HBL. I didn't say "WUP Installer" I said "WUP server". Two very different things. Hold tight though. I found a solution for you. I'm working on typing up the instructions.
The basic steps are:
1. Make sure DNS blocking is enabled on 5.5.2
2. Use hexFW fw.img to dump your otp.bin and seeprom.
3. Downgrade your firmware to 5.5.1 using these new sysnand dumps
4. Double check DNS blocking on 5.5.1
5. Access HBL through webexploint on 5.5.1
6. Fix HaxChi by reinstalling with a proper config
7. ???
8. Profit
(steps 7 and 8 are a joke from South Park)
I'll come back and be way more specific after I compile the hexFW fw.img file for you
Edit: Hmmmm. Looks like this method would work but you'd have to perform a hardmod and lots of micro soldering. Well at least you can go through the steps to backup your otp.bin and seeprom. Get the other files too if you have room. Gimme a minute. I'll have a fw.img for you to launch soon
There has got to be a way to get into sysnand HBL with a fw.img file. The quest continues!