The MX25L25645GZ2I-08G is a 256Mb (32MB) SPI NOR Flash from Macronix in SOIC-16 (300mil width), supporting standard SPI, Dual I/O, and Quad I/O modes at up to 133MHz. The SOIC-16 package provides dedicated WP# and HOLD# pins that can be repurposed as IO2/IO3 in quad mode, enabling 4-bit parallel data transfer. At 133MHz in QIO SDR mode, the read bandwidth reaches 66MB/s; in QIO DDR mode at 80MHz, 80MB/s. The memory is organized as 512 sectors of 64KB, with 4KB sub-sectors for fine-grained erase. The device supports 256-byte page programming (0.3ms typical), 4KB sector erase (0.15s), and 64KB block erase (0.8s). The endurance is 100,000 program/erase cycles per sector with 20-year data retention. The security features include: 3 x 256-byte security registers with factory-programmed 64-bit unique ID, individual sector/block lock for write protection, and a one-time programmable (OTP) area. The device supports XIP (eXecute In Place) for direct code execution without RAM shadow. The QE (Quad Enable) bit in the status register must be set via SPI command (write status register) before using quad mode. The deep power-down mode reduces current to 5uA. The -Z2I suffix specifies SOIC-16 300mil, industrial temperature (-40C to +85C). The -08G suffix specifies 133MHz speed grade. Applications include: BIOS/UEFI firmware storage, FPGA configuration, embedded Linux root filesystem, and XIP code storage.