Uploaded firmware file is too large

Hello all, getting this browser pop up trying to load in a new firmware version using EPM Custom Firmware Management.

Uploaded firmware file is too large

The firmware is 753MB.

I have already turned up both the upload_max_filesize and the post_max_size to well above that. The PHP Info page confirms I have successfully made the change.

Despite the error the file also is correctly uploaded to the TFTP directory, it just does not create a row in the custom FW management screen, so it looks more like it might be an issue with EPM rather than a web server issue.

What do I try next?