QSPIFormat sketch – LED blinking after QSPI erase (4 slow + 4 fast)

## QSPIFormat sketch – LED blinking after full QSPI erase (4 slow + 4 fast)

### Description

I am using the `QSPIFormat` sketch to prepare the Portenta H7 board for OTA updates, following the official Arduino documentation:

https://docs.arduino.cc/software/plc-ide/tutorials/memory-partitioning/

As described in the documentation, the sketch requires:

1. Pressing `Y` + `Enter` to confirm partition creation
2. Pressing `Y` + `Enter` again to confirm full QSPI erase

The full erase procedure completes successfully according to the serial log. However, immediately after the erase is completed, the board LEDs start blinking:

- 4 slow blinks
- followed by 4 fast blinks

This pattern repeats continuously.

### Expected behavior

After successfully completing the QSPI erase/format operation, the board should either:

- Continue with partition creation, or
- Clearly indicate successful completion

The board should not enter what appears to be an error LED pattern.

### Actual behavior

As soon as the full erase completes, the LED blinking sequence (4 slow + 4 fast) starts and does not stop.

### Serial log output

11:05:04.836 -> The following partitions will be created:
11:05:04.836 -> Partition 1: WiFi firmware and certificates 1MB
11:05:04.836 -> Partition 2: OTA 5MB
11:05:04.836 -> Partition 3: Provisioning KVStore 1MB
11:05:04.836 -> Partition 4: User data / OPTA PLC runtime 7MB
11:05:04.836 -> Do you want to proceed? Y/[n]
11:05:08.258 -> Do you want to perform a full erase of the QSPI flash before proceeding? Y/[n]
11:05:08.258 -> Note: Full flash erase can take up to one minute.
11:05:10.198 -> Full erase started, please wait...
11:06:18.177 -> Full erase completed.

After this message, the LED blinking pattern starts.

### Steps to reproduce

1. Flash the `QSPIFormat` sketch on the Portenta H7.
2. Open Serial Monitor.
3. Confirm partition creation by pressing `Y` + `Enter`.
4. Confirm full erase by pressing `Y` + `Enter`.
5. Wait for "Full erase completed."
6. Observe the LED behavior.

### Additional information

- Board: Portenta H7
- IDE: Arduino IDE
- Custom modifications: None

Start with the QSPIFormat sketch and reproduce the Portenta H7 sequence through the serial message “Full erase completed.” Observe the 4 slow plus 4 fast LED pattern and trace what follows the erase completion; done means the erase completes without the repeating error-like pattern and the sketch clearly continues or reports success.

Written by the indexing model from the issue text.