The HP Pro 3500 MT is too reliable in all other aspects to be scrapped due to corrupted firmware. By following this guide—from locating the W25Q64 chip to programming a clean BIN—you have restored full functionality. The black screen is gone. The beeping codes are silenced. Your old workhorse is back in service.
We recommend starting with the non-invasive as it is safe and simple. If that fails, the EEPROM programmer (CH341A) approach is a highly reliable and direct solution that bypasses a potentially broken boot block altogether. Both are valuable tools for any PC repair enthusiast. With some patience and the right tools, you'll have your HP Pro 3500 up and running again. hp pro 3500 series mt bios bin file fix