The factory samples (Sample Bank A, Sample Bank B Pads 1 and 2) and patterns (Pattern Bank A) assigned to the SP-404 at the factory can be downloaded from the following page.
SP-404 Factory Data: https://www.roland.com/global/support/by_product/sp-404/updates_drivers/
A CompactFlash card formatted on the SP-404 is required to load the data. Extract the downloaded file, copy it to the CompactFlash card, and then load it on the SP-404. For detailed instructions, refer to the Readme file (PDF) in the factory data folder.
Note: This operation overwrites the settings on the unit with the backup data. Back up any data you do not want to lose before performing this operation.