update:
tried to unpack my modified .iso and check a bunch of text files contained
inside squashfs file - they are readable and seem to be as they should be
tried to make boot flash drive from modified .iso with rufus and hen replace
flash drive's contents (except squashfs file) with
yes, that's what I called "mangled"
I did not change anything in my settings so should be whatever encoding
trisquel 8 uses by default
I see weird characters. Which coding do you use?
UPDATE:
unpacked both original *.iso image and "remastered" and compared: almost all
files are different.
for example \isolinux\isolinux.cfg file unpacked from original *.iso contains
following text:
# D-I config version 2.0
include menu.cfg
default vesamenu.c32
prompt 0
timeout 300
ui
Obviously, your USB drive was indeed "bootable", otherwise you wouldn't see
syslinux's error messages, only that you have to correct the configuration
files.
You may need to read syslinux's documentation. I recently tried to remaster a
Debian Live USB and managed to make the persistence
tried to "remaster" trisquel 8 iso (64bit, default 2.6 Gb edition) using
these instructions:
https://trisquel.info/en/wiki/customizing-trisquel-iso
resulting iso was only 2.2 Gb (the only change I made is installing tiny
2048-qt package, to test if remastering process works)
after making