When I load up WEACT_F411_BLACKPILL-V31_FLASH_8M-20251209-v1.27.0.hex

[davefes]

Documentation URL

No response

Description

and run it I am told that it is:
MicroPython v1.27.0 on 2025-12-09; WEACT_F411_BLACKPILL with STM32F411CE

Code of Conduct

Yes, I agree

[Josverl]

Please specify:

• the exact source/location where you got the firmware from
• the hardware you loaded it on
• how you flashed it

[davefes]

1. from the Micropython download site
2. a new 8MB WeACT STM32F411 Blackpill v3.1
3. using the STM32CubeProgrammer on a Linux Ubuntu machine

[robert-hh]

What is the issue? You get what should be expected.

[davefes]

I expected it to be more specific. I was running the default firmware on this board, and again experienced the problem I had:
https://github.com/orgs/micropython/discussions/17650
so, I thought it best to put the 8MB firmware (25MHz xtal) on the board before getting too excited.

I am now unsure which firmware version is being run. I did a full chip erase. Uploading .dfu firmware seems difficult c.f. .hex files.

[robert-hh]

Since you get a REPL response, at least the crystal matches the firmware. Can you tell which crystal is at the board? It's engraved at the crystal. You should be able by looking at the board, whether the 8 MB flash is present or not. You can check in REPL with

import os
os.statvfs("")

That will show the size of the flash file system. If that reports 8MB (block_size * block_count), then the flash is present and used.

[robert-hh]

I'll convert that to a discussion. Does no look like an issue.

[davefes]

This version and the default use a 25MHz xtal, which is present on the board. The added flash is also there. I will check with os.statvfs("").

[shariltumin]

I don't know if these are relevant.

Standard MP:

MicroPython v1.27.0 on 2025-12-09; WEACT_F411_BLACKPILL with STM32F411CE
Type "help()" for more information.
>>> 
>>> import os
>>> os.statvfs("")
(0, 0, 0, 0, 0, 0, 0, 0, 0, 128)
>>> os.listdir()
['flash']
>>> os.statvfs('flash')
(4096, 4096, 2043, 2039, 2039, 0, 0, 0, 0, 255)
>>> os.listdir('flash')
['boot.py', 'main.py', 'pybcdc.inf', 'README.txt']
>>> 

My Custom build:

MicroPython v1.28.0-preview.62.g0fd084363a.kaki5 on 2026-01-14; STM32F411CEU6 WeACT 8MB Wiznet with STM32F411CE
>>> 
>>> import os
>>> os.statvfs('')
(4096, 4096, 2043, 2039, 2039, 0, 0, 0, 0, 255)
>>> os.listdir()
['boot.py', 'main.py', 'pybcdc.inf', 'README.txt']
>>> 

So, I suppose all file open operations require the "/flash/" prefix for standard MP.

[Josverl]

Or a _boot.py/boot.py that changes the cwd to a mountpount with a mounted filesystem.