Recently a new patent by a SONY employee was published on the patent site at faqs.org. It seems it is SONY's answer for Geohot's progress. Take a look here:
"A method, system, and computer-usable medium are disclosed for controlling unauthorized access to encrypted application program code. Predetermined program code is encrypted with a first key. The hash value of an application verification certificate associated with a second key is calculated by performing a one-way hash function. Binding operations are then performed with the first key and the calculated hash value to generate a third key, which is a binding key. The binding key is encrypted with a fourth key to generate an encrypted binding key, which is then embedded in the application. The application is digitally signed with a fifth key to generate an encrypted and signed program code image. To decrypt the encrypted program code, the application verification key certificate is verified and in turn is used to verify the authenticity of the encrypted and signed program code image. The encrypted binding key is then decrypted with a sixth key to extract the binding key. The hash value of the application verification certificate associated with the second key is then calculated and used with the extracted binding key to extract the first key. The extracted first key is then used to decrypt the encrypted application code."