Yay! Problem solved. Thank you for your help.
So here is what I did.
1. Download the mmc_format.py file from here:
https://pybd.io/resources/mmc_format.py
2. Copy and past to main.py and reboot.
3. Open up repl and call mmc_format() <- you can be sure that the function is available by calling dir(). It should be listed there.
Once formatted, the storage needs to be handled just like an sd card.
e.g., mount: os.mount(pyb.MMCard(), '/mmc')
append partition to path: sys.path.append('/mmc')
and now you can os.chdir('/mmc') and voila!
The more I understand this board the more I am amazed at how capable a device it is!
Here is the format script in case the above link ever changes.
# Support functions for a factory format of WBUS-EMMC
FAT = """000001b0 00 00 00 00 00 00 00 00 98 96 af 9c 00 00 00 21 |...............!|
000001c0 03 00 06 17 ea fd 00 08 00 00 00 f8 71 00 00 00 |............q...|
000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|
00100000 eb 58 90 6d 6b 66 73 2e 66 61 74 00 02 08 20 00 |.X.mkfs.fat... .|
00100010 02 00 00 00 00 f8 00 00 3e 00 76 00 00 08 00 00 |........>.v.....|
00100020 00 f8 71 00 70 1c 00 00 00 00 00 00 02 00 00 00 |..q.p...........|
00100030 01 00 06 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00100040 80 00 29 88 8c 78 e6 50 59 42 4d 4d 43 20 20 20 |..)..x.PYBMMC |
00100050 20 20 46 41 54 33 32 20 20 20 0e 1f be 77 7c ac | FAT32 ...w|.|
00100060 22 c0 74 0b 56 b4 0e bb 07 00 cd 10 5e eb f0 32 |".t.V.......^..2|
00100070 e4 cd 16 cd 19 eb fe 54 68 69 73 20 69 73 20 6e |.......This is n|
00100080 6f 74 20 61 20 62 6f 6f 74 61 62 6c 65 20 64 69 |ot a bootable di|
00100090 73 6b 2e 20 20 50 6c 65 61 73 65 20 69 6e 73 65 |sk. Please inse|
001000a0 72 74 20 61 20 62 6f 6f 74 61 62 6c 65 20 66 6c |rt a bootable fl|
001000b0 6f 70 70 79 20 61 6e 64 0d 0a 70 72 65 73 73 20 |oppy and..press |
001000c0 61 6e 79 20 6b 65 79 20 74 6f 20 74 72 79 20 61 |any key to try a|
001000d0 67 61 69 6e 20 2e 2e 2e 20 0d 0a 00 00 00 00 00 |gain ... .......|
001001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|
00100200 52 52 61 41 00 00 00 00 00 00 00 00 00 00 00 00 |RRaA............|
001003e0 00 00 00 00 72 72 41 61 df 37 0e 00 02 00 00 00 |....rrAa.7......|
001003f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|
00100c00 eb 58 90 6d 6b 66 73 2e 66 61 74 00 02 08 20 00 |.X.mkfs.fat... .|
00100c10 02 00 00 00 00 f8 00 00 3e 00 76 00 00 08 00 00 |........>.v.....|
00100c20 00 f8 71 00 70 1c 00 00 00 00 00 00 02 00 00 00 |..q.p...........|
00100c30 01 00 06 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00100c40 80 00 29 88 8c 78 e6 50 59 42 4d 4d 43 20 20 20 |..)..x.PYBMMC |
00100c50 20 20 46 41 54 33 32 20 20 20 0e 1f be 77 7c ac | FAT32 ...w|.|
00100c60 22 c0 74 0b 56 b4 0e bb 07 00 cd 10 5e eb f0 32 |".t.V.......^..2|
00100c70 e4 cd 16 cd 19 eb fe 54 68 69 73 20 69 73 20 6e |.......This is n|
00100c80 6f 74 20 61 20 62 6f 6f 74 61 62 6c 65 20 64 69 |ot a bootable di|
00100c90 73 6b 2e 20 20 50 6c 65 61 73 65 20 69 6e 73 65 |sk. Please inse|
00100ca0 72 74 20 61 20 62 6f 6f 74 61 62 6c 65 20 66 6c |rt a bootable fl|
00100cb0 6f 70 70 79 20 61 6e 64 0d 0a 70 72 65 73 73 20 |oppy and..press |
00100cc0 61 6e 79 20 6b 65 79 20 74 6f 20 74 72 79 20 61 |any key to try a|
00100cd0 67 61 69 6e 20 2e 2e 2e 20 0d 0a 00 00 00 00 00 |gain ... .......|
00100df0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|
00104000 f8 ff ff 0f ff ff ff 0f f8 ff ff 0f 00 00 00 00 |................|
00492000 f8 ff ff 0f ff ff ff 0f f8 ff ff 0f 00 00 00 00 |................|
"""
def _mkfs(bdev, fat):
lar = fat.split('\n')
cbla = -1
for x in lar:
xar = x.split(' ')
if len(xar) >= 17:
a = int(xar[0], 16)
bla = a >> 9
offset = a & 0x1ff
if bla != cbla:
if cbla >= 0:
bdev.writeblocks(cbla, ba)
print('%x' % (cbla*512))
ba = bytearray(512)
cbla = bla
print(x)
print(end='%08X' % (a))
for i in range(16):
ba[offset+i] = int(xar[1+i], 16)
print(end=' %02X' % (ba[offset+i]))
print()
for x in ba:
if x:
bdev.writeblocks(cbla, ba)
print('%x' % (cbla*512))
break
def mmc_format():
import pyb
mmc = pyb.MMCard()
mmc.power(1)
print('Formatting...')
_mkfs(mmc, FAT)
print('Done')
print('Run mmc_format() to format the WBUS-EMMC flash memory')