The latest BIOS for Zida or Tomato boards, model TX98 - 3D. This is the latest BIOS, but an unofficial one. It worked on my board just fine (I use an AMD K6-III+ 450 on it, but if you set the jumpers to FSB 83 MHZ and multiplier 2x, you get 500 MHZ because the processor interprets 2x as 6x! Very stable, no overheating, no problems.). Look for the pdf manual as well, I will upload it after I upload this BIOS update.
Also, if anyone has one such motherboard (functional, please) to spare, I will be happy to buy it, please e-mail me (I have Paypal).