circuitpython: [pygamer] IOError when reading files from SD card

Hi, I just figure out that there is a ‘slight’ difference when reading files from the flash or from the SD card.

Version: master (6/16/2019)

File generation (copied to the flash and to the SD card

time dd if=/dev/urandom of=test.dat bs=1 count=1M

Code:

import sys
import os
import adafruit_sdcard
import board
import busio
import digitalio
import storage

# Connect to the card and mount the filesystem.
spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
cs = digitalio.DigitalInOut(board.SD_CS)
sdcard = adafruit_sdcard.SDCard(spi, cs)
vfs = storage.VfsFat(sdcard)
storage.mount(vfs, "/sd")
sys.path.append("/sd")
os.chdir("/sd")

buf = bytearray(160*128)
f = open('test.dat', 'rb')
f.readinto(buf)
f.close()

Results on the SD card:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: [Errno 5] Input/output error

works well from the flash. os.listdir() works, files located on the SD card are shown

Any idea when I can check ? Libraries ?