UPDATE: (sorry for the double post but want to be sure you guys see this)
It has been CONFIRMED that the Japanese version of Coded Arms does NOT force update to 1.51-1.52, only to v 1.5 of the firmware. Several people have confirmed that they have bought the Japanese Coded Arms and allowed it to update and it went to 1.50, and they are still able to run homebrew with the new hacks.
Of course, still no word on US or UK versions, but this is a good sign, and since the Japanese and US versions are not releasing that far apart, and since there seems to be a BIG delay between when sony releases these FW updates before you start seeing them in games, I'm gonna bet money that the US Coded Arms may only update to 1.5. Well technically it wouldn't even have an update at all since all US systems are 1.5 already
So... POSSIBLE good news. If worse comes to worse I may just buy a Japanese one for myself, price should come down a bit after the US one releases.
Also, some people at psp2dev seem to have already found a possibly exploitable bug in v's 1.51 and 1.52 that is very close along the lines of what they are using to run homebrew on 1.5. So hacks for the newer versions may not be far off.
EDIT: here's some more info from one person on psp hacks forums:
http://www.psp-hacks.com/forums/about1153.html
Sounds like people who wanted Coded Arms won't be screwed after all.