---- On Tue, 23 Oct 2018 11:21:33 +0200 luigi scarso <luigi.scarso@gmail.com> wrote ----
 >
 >
 > On Tue, Oct 23, 2018 at 10:53 AM Marcel Krüger <tex@2krueger.de> wrote:
 > Hi,
 > 
 >  another bug in LuaTeX: If LuaTeX tries to calculate the size of a CFF table where the second entry in the table is a real number,
 >  `pack_real` is called with `work_buffer+i` for a small `i`.
 >  This causes aliasing issues because `work_buffer` writes into `work_buffer` using `sprintf`.
 >  So the output from `pack_real` modifies `work_buffer` before the digits are read completely,
 >  causing LuaTeX to complain about a "invalid character".
 > 
 >  An example to reproduce the issue:
 > 
 >  Run the following plainTeX document with the attached version of `LOGO10.otf` (the font was created by reordering
 >  the Private table entries and has an invalid checksum, but this is ignored by LuaTeX)
 > hm, not sure about invalid checksum... can you try to fix it with ttx  ? (be careful, change the name of the new otf ie  CFFFont name etc)
 > --luigi

I already tried, but tty always stores the BlueValues first. I originally triggered this when I had a font which had fractional BlueValues which
are replaced by whole
So fixing the checksum would need some other tool or manual calculation, but I do
not think it is worth it: LuaTeX does not care (I regularly use auto-generated fonts with all checksums set to zero
without problems)
Also there are no checksums in the actual CFF part, only in the OTF wrapper which is mostly ignored anyway.