@Onee-chan In an Entware-ish style like what's been done for AsusWRT, it should be possible. Integrated with the firmware, it's yet another binary blob and a huge one, so for God's sake let's forget about it. Anything that needs a GUI change, along with further coding at ~/router/rc/ (most initialization code is there), it's a major PITA to deal with. You can potentially spend 1 day figuring out how to do a "small change" without breaking anything else. Anything within ~/router/rc/ is a high impact change.