Note please review the following article before carrying to the steps listed below as there is another possible cause of the 'Upload Failed' error.
To complete the manual upgrade of VMware Aria Operations, follow the steps below.
curl --include --request POST --form 'pak_handling_advice="CLOBBER"' --form "contents=@/storage/db/tmp/Pak_Name.pak" --insecure --user 'admin:<password>' https://Primary_Node_IP/casa/upgrade/cluster/pak/reserved/operation/silent_install
curl --include --request POST --form 'pak_handling_advice="CLOBBER"' --form "contents=@/storage/db/tmp/vRealize_Operations_Manager_With_CP-8.x-to-8.12.0.21786724.pak" --insecure --user 'admin:<password>' https://x.x.x.x/casa/upgrade/cluster/pak/reserved/operation/silent_install
Impact/Risks:
It is recommended to take snapshots following How to take a Snapshot of VMware Aria Operations before upgrading.