Need help to use a 'data' partition on ESP32

[Tangerino]

I recompiled MP 1.19.1 and build the following partitions

ID Type   Subtype   Address  Size     Label    Encripted
 0   0      0         65536  2031616  factory  False
 1   1      2         36864    24576  nvs      False
 1   1      1         61440     4096  phy_init False
 1   1      129     2097152  2097152  vfs      False
 1   1      129     4194304  4194304  data     False

And I'm trying to mount (and optionally format) the data partition where I intend to store telemetry data.

The code I ran

import os
import errno
from esp32 import Partition


def disk_free(volume_name: str, verbose: bool = False) -> int:
    space = 0
    try:
        parts = os.statvfs(volume_name)
        space = parts[0] * parts[3]
    except Exception as e:
        print(f"[DISK] Error getting disk free space for {volume_name} - {e}")
    return space


def display_partition_info(name, msg: str):
    print(f"Partition info for {name} - {msg}")
    print(f"Partition info for {name}")
    print(f"Partition size is {disk_free(name)} bytes")
    print("Files in partition:")
    print(os.listdir(name))


def format_partition(partition, mount_name: str) -> bool:
    try:
        try:
            os.VfsLfs2.mkfs(partition)
        except Exception as e:
            print(f'Error formatting partition - {e}')
        else:
            print('Partition formatted')
            try:
                os.mount(partition, mount_name)
                display_partition_info(mount_name, msg="#2")
            except Exception as e:
                print(f'format_partition - Error mounting partition - {e}')
            else:
                print('Partition mounted')
                return True
    except Exception as e:
        print(f'Unhandled error: {e}')
    return False


def mount_telemetry_partition(partition, mount_name: str):
    try:
        print(f"Mounting `{mount_name}` partition")
        os.mount(partition, mount_name)
        display_partition_info(mount_name, msg="#1")
    except OSError as e:
        if e.errno == errno.ENODEV:
            print(f'No such device - {e} - `{mount_name}`')
            ok = format_partition(partition, mount_name)
            if ok:
                print('Partition formatted and mounted')
            else:
                print('Partition not formatted')
        else:
            print(f'Error mounting partition - {e}')
            ok = format_partition(partition, mount_name)
            if ok:
                print('Partition formatted and mounted')
            else:
                print('Partition not formatted')


def build_telemetry_partition():
    header = "ID Type   Subtype   Address  Size     Label    Encripted"
    print(header)
    for partition_id in range(10):
        partitions_info = Partition.find(partition_id)
        if partitions_info:
            for partition in partitions_info:
                p_type, subtype, addr, size, label, encrypted = partition.info()
                # format line to match header
                line = f"{partition_id:2d}   {p_type: <6} {subtype: <6} {addr:8d} {size:8d}  {label: <8} {encrypted}"
                print(line)
                if label == 'data':
                    mount_telemetry_partition(partition, "/data")
    print('Done')

The first I ran this code I was able to listdir() then all subsequent tries failed as in:

>>> build_telemetry_partition()
ID Type   Subtype   Address  Size     Label    Encripted
 0   0      0         65536  2031616  factory  False
 1   1      2         36864    24576  nvs      False
 1   1      1         61440     4096  phy_init False
 1   1      129     2097152  2097152  vfs      False
 1   1      129     4194304  4194304  data     False
Mounting `/data` partition
Error mounting partition - [Errno 1] EPERM
Partition formatted
format_partition - Error mounting partition - [Errno 1] EPERM
Partition not formatted
Done

Any idea how to do it right?

Thanks in advance

[Tangerino]

It seems I have to mount the partition inside boot.py