Linksys RE6500 need help recompiling for bigger flash chip

No.
Marking a topic solved and then deleting it after some days would be crazy.
Please read How to mark a topic as [Solved] to get a better understanding what this does and why it is a useful thing to do.

If you want to be really helpful, you could post a summary of the actions that lead to a working status, and then mark your posting as the solution.