How to unlock the Readout protection by STM32CubeProgramer through USART

[STM32L09]

I soldered a new STM32 on the board, it can enter bootloader, but it's under Readout protection(I guess I bought renovated chip), I don't know how to unlock Readout by STM32CubeProgramer, finally, I use STVP and ST-LINK V1 to connect through SWD, and change the option byte, unlock Readout protection.

I don't want to use ST-LINK and STVP, because I need to have SWD interface on the PCB(the PCB space room is very limited). I want to use STM32CubeProgramer through USART to set option byte, but I didn't find out how to set option byte if the chip is Readout protected.

[AScha.3]

Can you connected in bootloader do a : full erase chip, or mass erase ?

 

[STM32L09]

I supposed I can, we should able to unlock by erase the whole chip, but seems I can't, it alway display a small window says"the chip is readout protected...", if I close it, and click wherever, it shows up again.

I will try it again when I am home, and paste screen shot here.