BRW Fingerboard (Removed) Warped

[onewent]

This BRW fingerboard was removed from the neck of a '42 Martin 00 recently .. the hide glue had given up the ghost, as did everything else on the neck that was glued including the ebony truss rod .. and it has a steep warp towards the end at about where the neck joins the body.
This causes two problems: 1. It's difficult to get the neck/board seam snug when regluing 2. Once reglued the warp will make the neck angle assessment more difficult than it needs to be, since it will 'spring' up when the neck is inserted into the dt/heel block.

I've already wetted and heated the board twice with my neck heater, to no avail. Any thoughts?
Thanks,
Tom

[onewent]

Hmmm, thought I added a pic .. ? I don't see the option now.

[Roger Häggström]

Wetting and heating is the way to go. Maybe you can give the fretboard an additional twist in the other direction while wetting&heating?

[Redacted]

And what stops the inevitable return to the warped condition caused by string tension when reassembled and 

re-strung?

[Roger Häggström]

Since the wood is aged, it is more stable and will not move as much. Time will tell, but my guess is that it will be stable for at least the next ten years. The heat will reset the lignin, acting much like plastic, to the new shape and freeze in the new position.

[onewent]

Thanks, Roger, I was thinking this might be my next step. Tom