SceNpDrm

Disable hash/signature verification
To find the function responsible for package verification search for immediate 0x7F504B47 ('.PKG'). Inside it does a lot of stuff including determining the function that will do signature checks. Find the condition that looks like ; below you will see the assignment. To bypass signature checks you need to patch two functions located at this offset and offset+4, making them behave as "return 1" is enough. For reference, on 1.60 the functions are sub_81000310 and sub_81000AA4. sub_81000310 is the only function in this module that calls SceSblGcAuthMgrPkgForDriver_E459A9A8_imp.

Note that on 1.60 this module sometimes is loaded at different addresses between reboots.

Allow debug packages to be installed
Find the function that calls SceSblAIMgrForDriver_D78B04A2; patch it to always return 1. On 1.60 it's at 0x81002d64.

Search for immediate 0x80870003, there should be two matches. Replace both with "MOV Reg, #0". On 1.60 the locations are 0x810035fe and 0x81004856.