Ran into the following error while trying to upload attachments to Gitea, which we migrated over the weekend to use Backblaze:

NewAttachment: Create: Unsupported header 'x-amz-checksum-algorithm' received for this API call.

As it turns out, according to go-gitea/gitea#23837, Backblaze doesn’t support the x-amz-checksum-algorithm header that Gitea is sending it, and there’s a configuration value to change Gitea to use the legacy md5 behavior that backblaze expects:

Gitea Documentation:

MINIO_CHECKSUM_ALGORITHM: default: Minio checksum algorithm: default (for MinIO or AWS S3) or md5 (for Cloudflare or Backblaze)

Setting this value should fix the error.