Nokia C3

Nokia C3 is an entry-level device released in August 2020.

vbmeta signature parsing
Following content is parsed from HMDSW_GMR-1040-0-00CN-B01_600CN_10_20200605_sprocomm_E6005N.devkit.pac.lzma2.[SHA256SUM].7z firmware. Hope it can be helpful for bootloader unlock key calculation. Minimum libavb version:  1.0 Header Block:            256 bytes Authentication Block:    576 bytes Auxiliary Block:         13568 bytes Algorithm:               SHA256_RSA4096 Rollback Index:          0 Flags:                   0 Release String:          'avbtool 1.1.0' Descriptors: Chain Partition descriptor: Partition Name:         boot Rollback Index Location: 1 Public key (sha1):      52be5dab4dea1313b824173667719d056808179d Chain Partition descriptor: Partition Name:         dtbo Rollback Index Location: 10 Public key (sha1):      52be5dab4dea1313b824173667719d056808179d Chain Partition descriptor: Partition Name:         recovery Rollback Index Location: 2 Public key (sha1):      abdb7f1028b247d8074cbaf64f436e75bf725a9e Chain Partition descriptor: Partition Name:         socko Rollback Index Location: 11 Public key (sha1):      cb2a7e23d7bfa29c4b7aeb5cf0a92b6dcc63c029 Chain Partition descriptor: Partition Name:         odmko Rollback Index Location: 12 Public key (sha1):      605bfce862206a8cbf4ab65e1fdc6bb1327ab388 Chain Partition descriptor: Partition Name:         vbmeta_system Rollback Index Location: 3 Public key (sha1):      3c03bda3a52708d51c3ea1f69f7e739e4f00eb75 Chain Partition descriptor: Partition Name:         vbmeta_vendor Rollback Index Location: 4 Public key (sha1):      720f86571aa64a77c1a49f034e6f8b8289d61e2d Chain Partition descriptor: Partition Name:         l_modem Rollback Index Location: 6 Public key (sha1):      cbb8bd85d34be4fa1212f44be8febf2118fc406d Chain Partition descriptor: Partition Name:         l_ldsp Rollback Index Location: 7 Public key (sha1):      cbb8bd85d34be4fa1212f44be8febf2118fc406d Chain Partition descriptor: Partition Name:         l_gdsp Rollback Index Location: 8 Public key (sha1):      cbb8bd85d34be4fa1212f44be8febf2118fc406d Chain Partition descriptor: Partition Name:         pm_sys Rollback Index Location: 9 Public key (sha1):      cbb8bd85d34be4fa1212f44be8febf2118fc406d

Permission Granting
All of Nokia C3 seems using the same auth response message with security version 105: BXJvMWRfMocDA6IbjeRgZ59ZQL5vuYgESoBvFApYSSpI0ISNBRV9ght6OwuHxl+u+2G66ZSa0ao5SWfCsRu3u/s6hiAb+M78Ht9DGPspwrYOvp8rdJIxZicGIJlRbK4QA4eDDQiBjFEOCxG5bmNejt2scDE/9g9VaXXdQL307EDXoIlCpBaaTWTBh1W7nw+VsJ25gh3NqcHevLQq3Snmh2wL5bRECaGGZmqZL0WDHMMR9cnOo/0bb2PpAiKBiJevP6cw1zGzr4vphvvNtwb0qnhMA0nxYZcqZkAVqHUGvgB5EL3WEM2ppKQ+pfGCu8CW4SSFrELPCeCFMjqXrEYLdw==

Bootloader Unlock Theory
You may use the special fastboot binary compiled by Unisoc, which contains this command: fastboot flashing unlock_bootloader /path/to/unlock/key/file

Unisoc has a Linux binary available, in fact fastboot-android.exe contained in OST LA also has this command available.