external flash memory lockup(0x90000000). How do I unlock external flash on my stm32h735G-DK protoboard? I tried to modify an example program to put data on the external flash and I have locked it up. It now prevents me from downloading a program to

[BRobb.1]

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[Tesla DeLorean]

Ok, need to change the topic into the STM32 MCU forum, and separate the Summary/Title from the body of the question.

>>I tried to modify an example program to put data on the external flash and I have locked it up.

What does that mean? What exactly did you do to it? It's going to be hard to know how to back-out what you did without knowing specifically what you did.

A Security Setting or Mode?

Repetitively over-wrote?

Can you connect with STM32 Cube Programmer, the stand-alone GUI?

Can you Mass-Erase the External Memory?

Has a Macronix MX25LM51245GXDI00, right?

[BRobb.1]

Yes I can erase each block except the block that I was programming in. It is the first block on the 0x90000000 external flash. I cannot seem to erase it with the stm32cubeprogrammer. I get and error.

[Tesla DeLorean]

Ok, that says the core (CM7 presumably) has locked up.

So flip the BOOT0 SW1 to the HIGH position.

Remove all power connectivity to the board.

Then reconnect and try and erase the User Program in the Main/Primary Flash

Repeat, power cycle a second time in necessary.

Once your code is removed, then try doing a Mass Erase or Read on the External Flash

[BRobb.1]

This is a screen shot when I tried to erase the flash.