This is the most critical part of the review. The Z240 uses Intel Management Engine (ME). If you download a generic bin file and flash it directly, you may experience:
If your computer isn't booting (no video), try a hard BIOS reset before attempting a chip re-flash: CMOS Battery: hp z240 bios bin file link
In these scenarios, no USB drive or key combination will help. You must physically flash the chip. This is the most critical part of the review
Always verify the checksum (MD5/SHA) of any BIOS file you download, even from HP’s site, to ensure integrity. even from HP’s site
Follow the prompts until you reach the screen asking to "Install," "Create Recovery USB," or "Copy."