Click on Controllers > SIMATIC S7-1200 > CPU . Select your specific CPU model (e.g., CPU 1214C DC/DC/DC).
Wait for the progress bar to finish. Once complete, click . Verifying the Installation and Configuring S7-1200 V4.3 Hsp0276 S71200 Cpu V4 3 Download
Firmware V4.3 introduces several critical security and communication enhancements for the S7-1200 hardware: Click on Controllers > SIMATIC S7-1200 > CPU
If your objective is to update the actual, physical S7-1200 CPU firmware from a lower version (e.g., V4.0, V4.2) to V4.3, you need the firmware files, not just the TIA Portal HSP. V4.2) to V4.3
The (Hardware Support Package) for the S7-1200 CPU V4.3
Look for the file named HSP_V1x_0276_001_S71200_CPU_V4.3.isp1x (the exact file extension and naming convention vary slightly depending on your TIA Portal version).