The file /etc/portage/profile/use.mask can be used to modify the profile use.mask, in particular to unmask locally some flags originally masked for the profile. However, these locally unmasked flags do not show up in ufed and thus cannot be set. (This is particularly annoying since there is no clean way to set these flags at least "manually" without editing /etc/make.conf *every time* after calling ufed, although currently the source command might be misused to this purpose). I guess the correct solution would be that ufed "appends" /etc/portage/profile to the list of directories to be read for the cascaded profile.
I happen to have that in the patch for bug #154628, I'm just waiting for it to be tested, since that specific bug is amd64-specific and I have no amd64 machine.
I had misread your comment 4 to #14628 and had (falsely) thought that this patch is already contained in 0.40-r4. I have amd64 and tested the patch now: The flags mmx sse sse2 (e.g.) showed up and were saved as any other flags. Locally unmasking also worked as it should (i.e. the unmasked flags were treated as any other "normal" flag). Local masking had the expected effect on "normal" flags like e.g. readline (i.e. readline did not show up anymore and was unselected). However, local masking had no effect on the "special" flags mmx sse sse2. This is not a real problem, of course...
(In reply to comment #2) > However, local masking had no effect on the "special" flags mmx sse sse2. Thanks for testing. As it turns out, that's because use.mask overrides package.use.mask in parent profiles, but I was only letting it override parent profiles' use.mask. A fixed patch is now in the tree (for ufed-0.40-r5), which also addresses your bug.
