[cypher]

Looking at your other posts it seems you've had your robos for a while now but it's not too late to go right back to basics with taming.
Even if you did it before I would use the tissue trick, putting a tissue or some plain white toilet paper up your sleeve for a few hours then putting it into the cage, keep doing that daily for a while so your robo has a chance to really get used to your scent & stop seeing it as a threat.
When you do put your hand into the cage always try to approach your ham from the front or side where they can easily see you not from above, let your ham come to you don't force your hand on it.
Good tips from meredithandyang about how to feed treats there so try to do that.
Take your time don't rush things.
How often do you clean?
Just spot clean as needed & never really do a full clean all at once, maybe once a month replace about a third of the substrate & always keep some of the old nest material & food hoard when you clean, this will help your ham to feel safe & secure, less fear generally should help prevent biting.