LinuxQuestions.org - Liveslak iso2usb error

Hi folks,
not a bash/scripting expert but thought I'd provide some feedback. Ran into the error below when setting up a liveslak usb and
was able to get the script to run by tweaking line 640 of iso2usb.sh,
from
FEAT_64BIT="-O '^64bit'"
to
FEAT_64BIT="-O ^64bit"

Tried tune2fs directly from Konsole, setting the filesystem option worked with or without single quotes, so not sure why it wouldn't work from iso2usb.
Cheers.

Code:

...

tune2fs 1.43.1 (08-Jun-2016)

Setting maximal mount count to -1

Setting interval between checks to 0 seconds

Setting reserved blocks percentage to 0% (0 blocks)

Invalid filesystem option set: '^64bit'

*** bin/iso2usb.sh FAILED at line 642 ***

...