There are bugs in the JIRA import process, JIRA (4.2.1 backup instant has been used in the import as JIRA instant), with tried different zip structure to import the attachments, attachments are fail to import.
And the structure of the attachments zip file are: (i tried one method at a time)
1) attachment folder on top level, followed by ISSUE_NUMBER folders, and followed by ISSUE_NUMBER-X folder
2) ISSUE_NUMBER folder on top level, followed by ISSUE_NUMBER-X folder
the (1) has been passed thru the validation when import, and confirm import appear, but (2) failed.
Even using (1) to import all the issues, the attachments inside all the issues is not correctly linked. And click on the link of the attachment will has the JIRA 404 (on-demand) screen.
Please suggest any solution on the problems. It will be even better if the project key amendments can be included as a full solution. Thanks.