STM32G030K6T6 fails to respond to bootloader I2C, revised

[FrankNatoli]

Have STM32G030K6T6 system that in bootloader mode fails to respond to I2C.
Am asserting BOOT0 pin 25, negating NRST pin 6, wait 500ms, asserting NRST pin 6, wait three seconds, then attempt to send MCU erase packet to I2C1 device address 0x56 but get NACK
DSLogic Analyzer shows good I2C write to 0x56 but NACK in response, see attached screenshot.
Was originally writing to 0x57, which was correct for earlier implementation for STM32H7B3I, but TDK noted that the correct address for STM32G030K6T6 is 0x56, and that succeeded, i.e., erasing flash and writing flash, exactly once.
Second and all subsequent times attempted, 0x56 is NACK-ed.
Could original "success" have corrupted MCU bootloader code?

[Tesla DeLorean]

It's all the other pins the loader is monitoring that would be the problem, activity, especially on the USART pins described in AN2606 could preempt connectivity via I2C.

What did you do it your original interaction? I can't see querying the version or reading memory would change the status-quo