LittleFS on Pyboard V1.1

[peterhinch]

I was surprised to find that my Pyboard still uses FAT. Note that I did the following with no SD card fitted.
I erased flash

$ pydfu.py -m

Built firmware and deployed

$ make BOARD=PYBV11 deploy

with this outcome

MPY: sync filesystems
MPY: soft reboot
MicroPython v1.26.0-preview.149.g92cab73c9.dirty on 2025-07-09; PYBv1.1 with STM32F405RG
Type "help()" for more information.
>>> import vfs
>>> vfs.mount()
[(<VfsFat>, '/flash')]

mpconfigboard.mk apears to specify LFS2

MCU_SERIES = f4
CMSIS_MCU = STM32F405xx
AF_FILE = boards/stm32f405_af.csv
ifeq ($(USE_MBOOT),1)
# When using Mboot all the text goes together after the filesystem
LD_FILES = boards/stm32f405.ld boards/common_blifs.ld
TEXT0_ADDR = 0x08020000
else
# When not using Mboot the ISR text goes first, then the rest after the filesystem
LD_FILES = boards/stm32f405.ld boards/common_ifs.ld
TEXT0_ADDR = 0x08000000
TEXT1_ADDR = 0x08020000
endif

# MicroPython settings
MICROPY_VFS_LFS2 = 1

# PYB-specific frozen modules
FROZEN_MANIFEST ?= boards/PYBV10/manifest.py

How come I'm still getting FAT?

[davefes]

mpconfigboard.mk for the WeACT BlackPill has the same line in it. I think what it is saying is that you can change it to LFS2 if you want to.

Mine comes up FAT.

[peterhinch]

I guess they keep FAT for people who want to use MSC mode. So how to convert? I tried

>>> import pyb, vfs
>>> bd = pyb.Flash()  # Get block device
>>> vfs.umount('/flash')  # Unmount and verify
>>> vfs.mount()
[]
>>> vfs.VfsLfs2(bd)  # Try to format
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: [Errno 5] EIO

[davefes]

I use for the WeACT BlackPill:

import os, pyb

os.umount('/flash')
os.VfsLfs2.mkfs(pyb.Flash(start=0))
os.mount(pyb.Flash(start=0), '/flash')
os.chdir('/flash')

[peterhinch]

Thank you, that works.

[davefes]

Great, it is really thanks to someone else.
https://github.com/nspsck/STM32F411CEU6_BlackPill_Micropython/blob/main/README.md