I had to make some necessary repairs behind the wonderboard and I ended up making 6x6 inches holes through the cement board. I have repair sheetrock in the past but this cement board looks difficult to repair. I have googled online on how to do the repairs but I could not find much. Thank you in advance for all who will answer.
Just like with drywall. And since you've already done that, you're in familiar territory. It's only the materials that are a little strange. You could do a little research on patching holes that size in drywall, just substitute wonderboard everywhere it says drywall and be well served. You can cut some patches out of scrap wonderboard to fill the holes you've made, and pin them in place by inserting screws in the gap between original and patch. If you want a little more security, add some lumber in the space of the wall to bridge the gap and attach your patch to the lumber. Then just butter the gap with mortar or grout mix. Sand with a concrete stone, job's done. Let the tiling begin. Good luck with it.
