hello, first of all. great site.
i just tried the "1.50 helper\downhelper"-EBOOT on my 1.50-psp. it created all the files in the proper folders. only, most of the files were 0(zero) kb. i wondered, if they werent too small, possibly. so I compared the final "DOWNDATER" folder i had created with the one, psp-hacks.com hosts: mine had 332kb, the one from psp-hacks.com had 13mb. I also noticed, that right after the 1.50-helper-eboot finished its work, my memstick said it had 0(zero)kb free space left, even though i had 1mb free in the beginning and the folder the eboot created only had 332kb. So: i deleted the "DOWNDATER"-folder and some more files from my stick (in the end i had 17mb free) and started the 1.50-helper-eboot again: guess what!? now i have a similar folder (13mb) to the one i downloaded from psp-hacks. Also my memstick said, that it had some more space left.
I guess that means, that you have to have at least 13mb free mem to init the 1.50-helper-eboot with your 1.50-psp.
okay, you could say: "n00b-mistake" (fortunately i had some time to notice, for my other psp, which i want to downgrade isnīt here yet ); but i think, that this might have been the reason for some of the bricked devices.
i hope this will help someone. Though my english is not the best...