A deserved "Well done" to the author, a good end to a tricky job. I wonder if it is possible to solder the two halves of a flex circuit directly together? That is, is it possible without the junction wires?
Scrape the top of one, the bottom of the other, apply solder pads to both sides then align the two and reflow the solder.
Theoretically yes, but it's harder to control the heat for the duration you need to do that. The flex substrate is pretty melty.
I would try it with a shovel tip and a whole lot of spares to get the technique down, but if I only had one shot, I think I'd go with the author's technique, one wire at a time. Perhaps with less gap between the ends, though.
I’ve done this many times and in smaller ribbons with narrower traces, this is a FPCB the substrate is kapton and it should whitstand soldering temps pretty well the trickiest ones are FFCs (the white ones)
Ah. Good to know. I actually attempted something like that before this particular fix and it didn't go well. Hence I "gave up" and did it the "hard" way by hand.
Scrape the top of one, the bottom of the other, apply solder pads to both sides then align the two and reflow the solder.