I didn't find it

I was taken in by historical revisionism. I thought the Bartenura was an early source for the custom of bonfires on Lag B'Omer (and I know I said I wouldn't talk about bonfires any more, but this is about the dangers of revisionism and how stupid I am).
I even cited the Bartenura correctly, that he writes that he saw the fires on 28th of Iyar. Then the editor corrects him and says he must mean the 18th of Iyar, which is the Yarzheit of the Rashbi.
Since I was looking for Lag B'Omer bonfires, that is what I found. If I had used my brain a bit I would have known firstly that the Bartenura would never have thought that Lag B'Omer was the Yarzheit of R' Shimon bar Yochai, because that is based on the kitvei AriZal (and another editorial emmendment) which wasn't written until at least 100 years later. And also, that 28th of Iyar is a real Yarzheit of someone more important to Yerushalayim - Shmuel HaNavi. There was an age old tradition to go to his grave on the 28th of Iyar, which only came to an end in 1948 when the Jordanians captured his grave and did not allow Jews to go there. His Yarzheit was eclipsed 19 years later when that date became Yom Yerushalayim, the day that Jews were once again allowed to go to his grave (but more importantly also allowed to go the kotel and the old city).
So there is no source for Lag B'Omer bonfires from the Bartenura. It was the 'editors' trying to make history fit with the reality as they dreamt it up. Unfortunately nowadays there is a lot of made up history - to the extent where nobody believes anything they read in any Jewish publication (I hope) nor in any Artscroll book. But don't think this is a new thing. Editors have been changing the facts of history for well over a century.
So, there is no medieval source for bonfires on Lag B'Omer (and my brother sent me 4 modern sources who are against the whole 'Meron', bonfire celebration thing). I have learnt not to trust meddling editors, and I feel like an idiot.
Thanks for reading.