I've already upgraded twice to the old Rogero 4.21 and downgraded twice , And upgraded once downgraded then back up again on the new Rogero v2 posted today , In the whole process Ive not bricked , Got a bit stuck here and there but no problems flashing.
Problems i had was losing all my data , Had to format hdd when downgrading , But Ive a feeling his next cfw will just be an upgrade straight to 4.30 , Because the latest version isnt spoofed to 4.25 , Which makes me think he wants it as low as possible for the upgrade process.
I got the unspoofed 4.21 and wont try SGK-spoof or any other... I've read that a version that came out before was pre-spoofed to 4.25 but got a higher brick-prob. And since I got no flasher I used the safer one. You mind checking yours? (just for others to have a reference)
Never the less, I'm using YAB for accessing PSN at the moment, but I think a lot of methods work now
Mine version is the same that you got (unspoofed 4.21), and i am in your exacly situation since i don't have a flasher. I've installed latest MultiMAN and latest ShowTime, no loss of data in any way, no more fix and updates, and finally i can manage PSVita content directly from PS3.
Actually i am not interested to much about PSN, but if in the future an easier and safer solution will be added into the CFW, it will be fine