I haven't got very far yet, but I'll post the patches I've found as I find them so those who want to can do some testing. If anyone else has patches for firmware 4.0.7523 then post them in this thread, and if you test any of them let us know whether they worked or not, and which device you tested on.
Instructions are the same as previous versions, but none of the patches are enabled by default. If you haven't used these patches before then best to wait until others have tested them, I'll create an "Instructions for patching firmware 4.0.7523" thread once most of the commonly-used patches have been found and tested.
These patches have been tested (on some devices):
Spoiler:
libadobe.so.patch:
`Remove PDF map widget shown during panning`
`Preserve PDF pan position across page turns`
libnickel.so.1.0.0.patch:
`My 10 line spacing values`
`My 24 line spacing values`
`Custom left & right margins` (Maybe something wrong with this?)
`Custom font sizes`
`Search in Library by default`
`ePub fixed top/bottom margins`
`ePub disable built-in body padding-bottom`
`Freedom to advanced fonts control` (display issue with dropdown font list, but functions okay.)
`Fix three KePub fullScreenReading bugs`
`Custom footer (page number text)`
`KePub fixed font sharpness`
`Custom page refresh options (1,2,3,...,12)`
`Custom page refresh options (1,2,4,8,16,32,64,128)`
`Always display chapter name on navigation menu`
librmsdk.1.0.0.patch: (These should all work as before, librmsdk has hardly changed.)
`Fix page breaks bug`
`Default ePub monospace font (Courier)`
`Default ePub sans-serif font (Gill Sans)`
`Force user line spacing in ePubs (Part 2 of 2)`
`Ignore ePub book Adobe XPGT stylesheet (page-template.xpgt)`
`Ignore ePub book CSS and Adobe XPGT stylesheets`
`Ignore ePub TOC navpoints`
nickel.patch:
`Disable reading footer`
`Custom reading footer style`
These patches are UNTESTED:
These patches are still missing: