two way you can have a try:
1.use mtk SN-Write-Tool(https://mega.nz/#!bGgS3CQA!2eX8H3OjC7dN_mkZkWQm4JoJhtQlOz9cQ8F0rHKPeIo) and firmware to rewrite mac address.
refer to: https://www.youtube.com/watch?v=yaR5w5iNXXA
2.download a backup-nvram-flashable zip(http://www.mediafire.com/file/xxragidd7aijovh/MAC%25E5%259C%25B0%25E5%259D%2580%25E5%259B%25BA%25E5%25AE%259A-CUBE-M5-%25E6%259C%25AC%25E5%259C%25B0%25E6%259B%25B4%25E6%2596%25B0.zip/file),use “ota upgrade”-“local upgrade” to flash the backup-nvram-flashable zip.and then reset factory settings or boot into recovery mode to operate “Wipe data and cache partition”
please try the second way first.
