The S25FL204K0TMFI043 is officially marked Obsolete by Infineon.
What the 4Mbit SPI NOR Flash means for your design
This is a 4Mbit (512K x 8) SPI NOR Flash memory — the SPI interface keeps the pin count low (just six signals including chip select and data lines), which is why it fits in a compact 8-SOIC package. The 85 MHz clock frequency gives a theoretical read throughput of about 10 MB/s in quad-I/O mode, though the actual sustained rate depends on the controller's SPI peripheral and the flash's internal access latency. This is fine for firmware updates or configuration storage where writes are infrequent; it is not a candidate for high-speed data logging.
The narrow 3.90 mm body width saves board space compared to wider SOIC packages.