The Problem
When using a Raspberry Pi with an M.2 SSD connected via HAT+, you might encounter a situation where the Pi refuses to boot from the SD card. This becomes particularly problematic if there’s an issue with the SSD’s FSTAB configuration, potentially leaving your Pi unbootable.
Initial Symptoms
- Pi only boots from M.2 SSD via HAT+
- SD card boot works only when M.2 SSD is disconnected
- Traditional solutions (Raspi-Config, boot file modifications) ineffective
- Invalid FSTAB mount on M.2 SSD blocking boot process
Solution: Bootloader Update Process
Prerequisites
- Raspberry Pi (Model 4 or 5)
- Blank SD card
- Raspberry Pi Imager software
- Monitor and keyboard
- Optional: M.2-SSD to USB-C adapter (for recovery purposes)
Step 1: Download and Prepare Recovery Image
# No actual commands needed - use Raspberry Pi Imager GUI:
# 1. Launch Raspberry Pi Imager
# 2. Click "Choose OS"
# 3. Navigate: Misc utility images > Bootloader (Pi 5 family) > Boot Recovery
Step 2: Flash and Update Bootloader
- Write the recovery image to SD card
- Insert SD card into Pi
- Power on with only essential peripherals connected (screen/keyboard)
- Wait for LED indicators:
Normal pattern: Rapid blinking > Solid light (10 seconds)
Note: Some units may continue blinking - proceed after 30-60 seconds
Step 3: Recovery Process
# Sequential boot process:
1. Power off Pi
2. Remove recovery SD card
3. Insert normal SD card and test boot
4. If successful, shutdown:sudo shutdown -h now
5. Connect M.2 SSD via HAT+
6. Boot should now prioritize SD card
Additional Recovery Tips
- Consider keeping an M.2 SSD to USB-C adapter for emergency repairs
- Useful for:
- Formatting SSD via Raspberry Pi Imager
- Repairing/formatting from regular computer
- Clean OS installations
Technical Notes
- This issue may arise from DD copy operations when cloning SD to SSD ??!! And all boot-order settings derived/needed to support that
- Affects primarily Pi 4 and 5 models due to EEPROM-based boot code
- Earlier Pi models store boot code on SD card
sources (references) & credits
Basically all input/information came from the websites below. So credits and thanks to those content creators and subject matter experts. The only reason I mainly copy/paste their content is to guarantee I have a backup for myself and because multiple times I had to change and adapt. So archiving the “scripts” as I executed it succesfully is inportant for me.
