SYSR cannot be changed

Hello. I use FPGA to access w6100 via parallel bus. I confirmed that by parallel bus, I successfully read and wrote the register. For example, I write to the register 0x4200 with value 0xcc. It is also 0xcc to read back. And value of the read 0x0000 is 0x61. But I write 0x41f5 0x3a, the value of the read 0x2000 is still 0xE2. Although the data sheet 0x41f5 is written only, I found that the return value of the read 0x41f5 was also 0x3a, that is, the value I wrote.

The problem is solved.