After edit 115200 by 9600 in RTD266xArduino.ino and specify 9600 in Baud Rate, i can connect and read status :
Only problem... impossible to finish the job.Connection successful!
Reading status info... done
Manufacturer ID: 0xC8 (Bright Moon Semiconductor Co., Ltd)
Device ID: 0x12 (T25S40)
JEDEC Manufacturer ID: 0xC8 (Bright Moon Semiconductor Co., Ltd)
JEDEC Memory Type: 0x40
JEDEC Capacity: 0x13 (512 KB)
For tests, i modify the background. It's slow, it takes 9 minutes to get to 100% and says to me:
Creating firmware backup file "firmware-2018-12-02-02-29-05.bin"... ok
Checking firmware... Error! Could not detect firmware.