Have you showed her the iolite shard? If memory serves, that is another artifact she will comment on, if shown it. There may be something else that one can show her .... but if there is, I've forgotten which piece it is.

Be very thorough when you first visit the Withering Palace; there are a lot of details to note about the courtyard. When I was trying to get this path to open, I thought I'd made a mistake somehow and it was only after leaving the place, talking to Oroi, and moving on to another site that Six finally broached the dialogue needed to continue on this route.

I did keep a few saves, but I'm not sure without loading 'em how close any are to the relevant point in my playthrough. It's late, so I can't check them out till tomorrow. I might have what you're looking for, though.

Aachen, thanks for the swift reply.

Some more info on some of your points:

I made several attempts during my second playthrough. By that I mean at various stages after I was satisfied that Oroi was "prepped" for the trigger I went through the withering palace. The first time around I had shown her only the crown (rebeske foil was not available, see my explanation above) and there was no option to show her the iolite crystal. My second time around I showed her crown, robot neckpiece, robot battery, and telescope. Third time around I showed her everything above including rebeske foil. By then I had gifted the iolite crystal to Huang, as I didn't get an option to show her.

When ever I go to the withering palace, I am usually fairly thorough. Each time I've gone through it (maybe 6 times?) I've done the following:
- Visited every room in the palace including every scrap or piece of paper, checked around the table/balcony area and the item underneath the bench on the top floor, and the mural room.
- Interacted with the altar and the inscription at its base.
- Deciphered the charcoal count (316).
- Interacted with the hopper eye and source multiple times, as well as the hole in the middle dropping the rock
- Interact with all 6 statues and the 5 inscriptions at their base (I have all dictionary words, so translating always goes fast)
- Go below underground and do full 360 run, including the other charcoal graffiti underground and the artifact that's in the dirt.
- Interact with the patch of light and scare her from running to the depth of the pit. (Various commentary about sounds and possibly servos/something down there)
- Go through Six's commentary about him sitting on a decorated/golden chair in the center
- Six's commentary about something not being right and hearing voices
- Wait for Six to finish his analysis of the broken by design hopper (neural mesh/physical matrix)

Eventually I run around in circles spamming Q and R, until all commentary is exhausted. The final time I did it, the last commentary was how Amadu would love to know about this place. This comment allowed to unlock a new option at Renaki/Amadu about sharing information on how to find the withering palace, he then gives you an artifact which allows you to triangulate heaven's vault.

I'm assuming that I must have gone too far in progressing through the sites that now Amadu's option took precedence over Oroi's. However, I was forced to do so out of need to unlock the rebeske foil. To do so I had to unlock the Aamir (since you send him to Maersi, giving you a reason to visit a 2nd time). To unlock Aamir/age of sail site I had to show the telescope found at the crater to Tapi for his golden globe/positional controller artifact. This in turn means I have to unlock the Renaki/Amadu triggers to access Amadu's observatory/crater site.

So either I missed a way to get to Maersi a second time (after Emperor's garden) early on to get the rebeske foil. Or the rebeske foil isn't needed and after withering palace the dialogue to unlock Oroi happens naturally in later stages of the game.

Either way I'd be 100% thankful for any saves.

Solved it.

Did a 4th playthrough and finally got it.
Few things I recommend doing: Don't attempt Gates of Iox as it messes with Renba's dig site, which in turn helps you gather knowledge on the Age of Sail. Some dialogue options are locked out when visiting the Cratered Moon that suggest Aliya doesn't fully understand the history of Age of Sail and/or Age of Steel correctly.
Additionally I recommend also hiding the crown from Six when finding it and sharing it with Oroi. You mention the crown to Oroi three times - once when handing it over, again when querying on her progress, and one last time when finding out that she tried it on and fried it. For the achievement you'll need to at least interact twice with her about the crown and share the Rebeske Foil. There are various ways of doing this, but it includes a second visit to Maersi at least early on, which means dealing with Aamir, the market moon, and Renaki sidelines.

Certain states in the game need to have advanced for the option to visit Oroi and bring her to the withering palace are unlocked. Aliya must have explored the withering palace enough to have the knowledge that miner's raided the place and released the robots. This means she needs to have enough of an understanding of Age of Sail and the Holy Empire. In my 3rd playthrough I noticed that this is achieved after visiting several sites, including Renba's Digsite, Emperor's Garden, and Domed Marketplace/Age of Sail site. You can do the Miner's Site before Withering, but it's not necessary. You don't need to visit Ancient Library. Six needs to have remembered extensively his past memories associated with the Withering Palace.

At some point while traveling the rivers there will be a dialogue option about Six not feeling well and Aliya will suggest visiting Oroi for help. Six will make a comment about Oroi being an amateur and an analogy to having a pig slaughterer as a heart surgeon. If you get this at any point after withering palace, when still on good terms with Oroi, you have unlocked the trigger and can go visit her. Hovering over Elboreth will also have some flavor text about what you can share with Oroi.

I missed out in my first and second playthrough mainly due to having Oroi's place ransacked (crown not hidden) and pursuing the gates of iox achievement in the latter run, which prolongs exploring sites forcing the Rebeske foil to enter the story too late.

Good luck everyone