I've reflashed my ET10K with 5.4.003, no settings restore, started Samba (needed an opkg update to get it to load ok.)
PC could see ET10K (asked for login credentials).
With browse network neighbourhood, ET10K could see Ultimo4k, but not itself. Ultimo4k could not see the ET10K.
The mounts I have on the Ultimo4k include the parameter vers=2.0 I couldn't work out how to force this onto browse network, so.......
Took a copy of /etc/samba from the working version of 5.4.003, and copied it into the non-working version. Now works ok (needed a yellow button rescan in browser.)
(To copy, I stopped enigma (telnet init 4), renamed /etc/samba to /etc/samba.orig, copied over the "old" version of /etc/samba, restarted with init 3, and then rebooted.)