RB493G NAND replacement

Hi! I experience a problem with increasing bad blocks (up to 80%) on my RB493G. Formatting NAND from bootloader didn’t help. So I’ve to reinstall RouterOS every week:( I’ve got an idea to buy a cheap version of routerboard, unsolder NAND chip from it and solder it on RB493G.

  1. What routerboard NAND chip is compatible with RB493G one?
  2. Is it enough only to replace NAND?
    Thanks!