The manual explicitly notes: USB boot is not available on Rev 1.0 unless "Legacy USB Support" is enabled. Without this setting, you cannot boot from a USB flash drive to install an OS.
If installing this motherboard inside a standard custom PC case, use this functional layout to map your individual 2-pin connectors: Lenovo Is6xm Rev 1.0 Motherboard Manual
Express chipset, which provides business-tier features like Intel vPro and stable manageability. four DDR3 DIMM slots supporting dual-channel memory up to (8GB per slot). Expansion Slots: 1 x PCI Express x16 (for dedicated graphics). 1 x PCI Express x1. 2 x legacy PCI slots. Connectivity & I/O The manual explicitly notes: USB boot is not
If your variant was pulled from a specific Small Form Factor (SFF) ThinkCentre, it might use a proprietary . In this case, you must purchase a 24-pin to 10-pin (or 14-pin) adapter cable online to use a standard retail power supply. 6. Jumper Settings & BIOS Maintenance Clearing CMOS / Resetting BIOS Forgotten Passwords four DDR3 DIMM slots supporting dual-channel memory up