I've tested reading from a GigaDevice GD25R256DYIG on flashprog v1.5 using a Pi Pico, and got a successful dump. This was on a Lenovo NM-D351 board. Attached below is the log file from the operation. I specified "GD25Q256E/GD25B256E/GD25R256E" as that was the closest to my chip that was available. I'll update later once I have tested a write function as well.