I am currently having the same problem. I am on Rogero 3.4 with the 4.21 spoof and when I try to update through the Recovery Mode I get this:
"No applicable update data was found.
Connect storage media that contains update data of version
2.70 or later, and then press the START and SELECT buttons
at the same time."
I have a usb with the PS3/UPDATE/PS3UPDAT.PUP file on it with 3.55OFW.