So make your life easier, download firmware with .sin_file_set extension from our forum download and flash it using s1tool
I downloaded the operating system with the extension sin_file_set forum
But getting this message:
Processing ACPU files PROCESSING: userdata_S1-SW-LIVE-7054-PID1-0002-S1-PARTITION.sin ERROR [0x0506: _sin_header_verification, err: 000A] HDR block not accepted Break. ERROR [S1_TA_Close, limited, err: 0010] FINISHED Elapsed: 17 secs.