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I think it might be due to the reason that I have the databus going bidirectionally (address bus is only one direction) and the 74LS245 is either too slow or the memory is too fast for the data to propagate normally.
Any tips on how to fix this?
Edit: I think I may have found a solution in http://forum.6502.org/viewtopic.php?t=1173. It looks like propagation delays is our friend, but since I route the WR signal outside of the 74LS245, this may cause some confusion. The solution is to put all the signals through to get the same delays. I haven´t tested it yet, but hopefully I get some time tonight to do so

Edit2: I found the bug and now it works. No extra 74LS245 needed, so the timing is fine.

Next step is to put in the 65C02..