The algorithm typically performs multiple rounds of hashing. Some versions use two CRC32 implementations combined with an IMEI-based salt.
The most recent iteration for newer Internet devices. Direct public calculators for v4 are rare or require paid services as the calculation method is not universally decrypted for public use. Technical Write-up: How It Works new algo huawei unlock code calculator
ket-c/huaweiv3calculator: Calculate the unlock code ... - GitHub The algorithm typically performs multiple rounds of hashing