I believe this issue is fixed in the latest upstream version of arp-scan which is git tag 1.9.8 on github.
mac-vendor.txt can now accept mac addresses as normal mac addresses with ":" or "-" separators and with the alphabetic characters in either upper or lower case. This allows you to paste mac addresses from arp-scan or ifconfig directly into mac.vendor.txt. Note that there is now an IEEE oui assignment for 90:18:7c, so you would need to add a more specific entry to mac-vendor.txt, e.g. 90:18:7c:48:dd:db<TAB>Vendor Details Thanks. Roy --
