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Nov 17, 2025 1:33 AM UTC
Solved

Flash memory size of STM32H743XGH6

The STM32H743XGH6 is specified to have 1 MB of Flash memory.
However, it seems that the following 2 MB address ranges are writable:
BANK1: 0x08000000 to 0x080FFFFF
BANK2: 0x08100000 to 0x081FFFFF

If the device really has only 1 MB of Flash, I would expect the usable ranges to be:
BANK1: 0x08000000 to 0x0807FFFF
BANK2: 0x08100000 to 0x0817FFFF
Also, when I executed an erase operation on BANK2, it started erasing from address 0x08100000.

My question is:
Are the following areas valid and safe to use?
BANK1: 0x08080000 to 0x080FFFFF
BANK2: 0x08180000 to 0x081FFFFF

Any clarification about the actual usable Flash memory area would be appreciated.

TDK
TDKBest answer
Nov 17, 2025 1:44 AM UTC

Only the 1 MB specified in the datasheet is tested and guaranteed to work. The additional 1 MB may be present but is not tested or guaranteed to function correctly (although most likely it works just fine).

 

This happens when the same die is used for multiple chips. The additional testing takes time.

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3 replies

TDK
TDKBest answer
Nov 17, 2025 1:44 AM UTC

Only the 1 MB specified in the datasheet is tested and guaranteed to work. The additional 1 MB may be present but is not tested or guaranteed to function correctly (although most likely it works just fine).

 

This happens when the same die is used for multiple chips. The additional testing takes time.

"If you feel a post has answered your question, please click ""Accept as Solution""."
mƎALLEm
ST Technical Moderator
Nov 17, 2025 2:05 PM UTC

@TDK wrote:

The additional testing takes time.


Therefore it costs more money. That's why the parts with 2M are more expensive than the ones with 1M even having the same die inside.

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Andrew Neil
Super User
Nov 17, 2025 2:11 PM UTC

As the others have explained, this is widespread.

And it's not just ST - you'll find it across the semiconductor industry.

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.