I tried to set readout protection via ST-LINK CLI - it's enabled and disabled correctly, but after RDP=0 I can't erase/write chip - I've got an error on write operation. Tested on 2 boards and both boards have same behavior.
e:\STM32 projects>"%PROGRAMFILES%\STMicroelectronics\STM32 ST-LINK Utility\ST-LINK Utility\ST-LINK_CLI.exe" -c SWD SWCLK=9 -OB RDP=1
STM32 ST-LINK CLI v3.6.0.0
STM32 ST-LINK Command Line Interface
[SWCLK=9]: SWCLK is obsolete. Use SWJCLK instead.
ST-LINK SN: 55FF6B067087534936162567
ST-LINK Firmware version: V2J37S7
Connected via SWD.
SWD Frequency = 950K.
Target voltage = 3.1 V
Connection mode: Normal
Reset mode: Software reset
Device ID: 0x466
Device flash Size: 64 Kbytes
Device family: STM32G0
Updating option bytes...
Option bytes updated successfully.
e:\STM32 projects>"%PROGRAMFILES%\STMicroelectronics\STM32 ST-LINK Utility\ST-LINK Utility\ST-LINK_CLI.exe" -c SWD SWCLK=9 -OB RDP=0 -ME
STM32 ST-LINK CLI v3.6.0.0
STM32 ST-LINK Command Line Interface
[SWCLK=9]: SWCLK is obsolete. Use SWJCLK instead.
ST-LINK SN: 55FF6B067087534936162567
ST-LINK Firmware version: V2J37S7
Connected via SWD.
SWD Frequency = 950K.
Target voltage = 3.1 V
Connection mode: Normal
Reset mode: Software reset
Device ID: 0x466
Device flash Size: 64 Kbytes
Device family: STM32G0
Updating option bytes...
Option bytes updated successfully.
Full chip erase...
The elf loader Mass Erase function fails.
Error occurred during flash mass erase!
