Purge the local cache, redownload the update file, and retest the SHA256 hash.
Never apply firmware or system updates directly to a live node without a fallback path.
release notes bundled with the update to see if it fixes specific bugs you are encountering. Could you clarify the context of this report? Are you experiencing with a current router? Do you need help with the installation steps for this specific version? Are you checking for compatibility with a specific hypervisor (like VMware)?