Recovery

If your Raspberry Pi 4 will not boot, it is possible that the SPI EEPROM has become corrupted.

To check, remove the SD card, disconnect the device from power, then reconnect it. If the green LED does not flash, you will need to reprogram the EEPROM:

  1. Download the bootloader
    SHA-256: 2c5610682edfa2c3a2a41832c687559d8f091b9e48abaeb8577cca2a0cc81839
  2. Extract it to an empty FAT-formatted SD card and insert it into your Raspberry Pi 4
  3. Connect the power and wait for the green LED to flash quickly

Notes:

  • The updated bootloader improves compatibility with HATs by changing the behaviour of HALT to keep the 3V3 pin powered (view the full bootloader release notes)

 

From: https://www.raspberrypi.org/downloads/