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Associate
April 27, 2026
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Booting from the Main Flash Memory on the STM32L4

  • April 27, 2026
  • 2 replies
  • 79 views

The STM32L476 does not have an nBOOT0 option bit in its option bytes. Is there a way to boot from the main flash memory without using the BOOT0 pin?

Best answer by KDJEM.1

Hello @ikaz and welcome to the community;

 

According to the reference manual, the main flash is selected as boot area when BOOT0 is 0.

Please look at table 4 in RM0351:

KDJEM1_0-1777279798209.png

Thank you.

Kaouthar

2 replies

KDJEM.1
KDJEM.1Best answer
Technical Moderator
April 27, 2026

Hello @ikaz and welcome to the community;

 

According to the reference manual, the main flash is selected as boot area when BOOT0 is 0.

Please look at table 4 in RM0351:

KDJEM1_0-1777279798209.png

Thank you.

Kaouthar

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Andrew Neil
Super User
April 27, 2026

@ikaz wrote:

Is there a way to boot from the main flash memory without using the BOOT0 pin?


What do you mean by that?

On this chip, BOOT0 is a dedicated pin with no alternate functions; it is never unavailable - so what's the reason behind not wanting to use it ?

Note that you can enter the system bootloader from application code: 

How to jump to system bootloader from application code on STM32 microcontrollers

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
ikazAuthor
Associate
April 27, 2026

Thank you for your reply.
My question was about what to do if, due to some error, the BOOT0 pin on the board hasn’t been properly configured.
It seems there’s nothing that can be done about the L476 after all. Thank you.