I had an idea, unusual I know, more surprising - it worked.
Flashed ET10K with 5.4.003, no settings restore. Started Samba (after opkg update) and network browser exhibited the documented problems.
Did a settings restore and then restored settings+plugins - Samba now working as expected.
There is one subtle difference with the samba directory before and after the settings restore.......
Code:
root@et10000:~# ls -lR /etc/samba*
/etc/samba.flash.orig:
drwxr-xr-x 2 root root 528 Dec 28 09:02 distro
-rw-r--r-- 1 root root 20 Dec 28 09:02 lmhosts
drwxr-xr-x 2 root root 376 Dec 28 09:02 private
-rw-r--r-- 1 root root 744 Dec 28 09:02 smb-user.conf
-rw-r--r-- 1 root root 95 Dec 28 09:02 smb.conf
/etc/samba.flash.orig/distro:
-rw-r--r-- 1 root root 61 Dec 28 09:02 smb-branding.conf
-rw-r--r-- 1 root root 1457 Dec 28 09:02 smb-global.conf
-rw-r--r-- 1 root root 586 Dec 28 09:02 smb-shares.conf
-rw-r--r-- 1 root root 29 Dec 28 09:02 smb-vmc.conf
-rw-r--r-- 1 root root 29 Dec 28 09:02 smb-vmc.samba
/etc/samba.flash.orig/private:
-rw-r--r-- 1 root root 430080 Dec 28 09:02 secrets.tdb
-rw-r--r-- 1 root root 204 Dec 28 09:02 smbpasswd
-rw-r--r-- 1 root root 80 Dec 28 09:02 users.map
root@et10000:~#
after settings restore.....
root@et10000:~# ls -lR /etc/samba
/etc/samba:
drwxr-xr-x 2 root root 528 Dec 28 09:06 distro
-rw-r--r-- 1 root root 20 Oct 8 05:12 lmhosts
drwxr-xr-x 2 root root 376 Dec 28 09:06 private
-rw-r--r-- 1 root root 744 Oct 8 05:12 smb-user.conf
-rw-r--r-- 1 root root 95 Oct 8 05:12 smb.conf
/etc/samba/distro:
-rw-r--r-- 1 root root 61 Oct 8 05:12 smb-branding.conf
-rw-r--r-- 1 root root 1457 Oct 8 05:12 smb-global.conf
-rw-r--r-- 1 root root 586 Oct 8 05:12 smb-shares.conf
lrwxrwxrwx 1 root root 13 Dec 28 09:06 smb-vmc.conf -> smb-vmc.samba
-rw-r--r-- 1 root root 29 Oct 8 05:12 smb-vmc.samba
/etc/samba/private:
-rw------- 1 root root 430080 Dec 28 08:57 secrets.tdb
-rw------- 1 root root 204 Dec 28 08:57 smbpasswd
-rw-r--r-- 1 root root 80 Oct 8 05:12 users.map
root@et10000:~#
So restoring the plugin produces the desired result, no need to use an old working copy of /etc/samba (although the effect is the same).
Anything else needed before I get back to the full image?