how to password reset in voltaire 4036 ?

i have voltaire 4036 but i don’t have password. Default passwords from admin, guest, root don’t work. I can boot in u-boot menu but i don’t know what should I do. Please help (((

this method Mellanox Voltaire 4036 VLT-3011s way to reflash OS / reset password https://community.mellanox.com/s/question/0D51T00006RVt7VSAT