As far as I know you can't actually leash with robots, that may have
changed or be something that I was unaware about, but I don't think it's a
thing.

On Thu, 12 Mar 2015 at 11:27 GoneNomad notifications@github.com wrote:

On OpenComputers v1.51 with both a Tier 2 and 3 Robot, I could not move a
Leash Upgrade into the Robot, neither during assembly nor afterwards into a
Tier 2 Upgrade Slot. I noticed it was not being highlighted in NEI while
hovering over the appropriate slot as well.

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#959.

@gjgfuj is correct, robots cannot use the upgrade for technical reasons (in short: because they are blocks), so it is disabled to avoid people building a useless robot. Similar to how a bunch of other cards/upgrades are disabled for specific devices (e.g. graphics cards for mircocontrollers).

So for once it's actually true: it's not a bug, it's a feature!

Just FYI @GoneNomad, you can use the leash upgrade with drones rather than
robots.

On Thu, 12 Mar 2015 5:37 pm fnuecke notifications@github.com wrote:

Closed #959 #959.

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#959 (comment)
.