PS2 for PS4 PKGs Guide or JKPatch PS4 Memory Tool by all means do, as recently Xemio (aka @g991) made available a PlayStation 4 Debugger with 5.05 OFW support called PS4Debug for developers to modify memory with.
Download: ps4debug-master.zip / GIT
To quote from the README.md on the tool: PS4Debug
A debugger with support for the PlayStation 4! Have a look at blank for a little example! I hope someone will come along and make a full featured debugger with this framework.
Currently supports firmware 5.05 only!
PS4 Source Discord ... https://discord.gg/WXgmWFh
Debug Watch PlayStation 4 Debugger