update README

Author: driver1998

README.md

@@ -50,5 +50,7 @@ cd $OLD_PWD
 - DiscEmu looks for ISO images at `isos` in the working directory, so `/mnt/data/isos` as configured above. You might want to mount a partition with large enough space to this directory.
 
 - Due to Linux kernel limitations, DVD images are not fully supported. Also there is a ~2.2GiB file size limit, there is a third-party patch to bypass this, see https://lkml.org/lkml/2015/3/7/388 for more details. \
-You can use my fork of the official buildroot image for DVD images, it also includes some kernel patches that improves compability:  https://github.com/driver1998/duo-buildroot-sdk/releases/tag/v0.1-discemu.
+You can use my fork of the official v1 buildroot image for DVD images, it also includes some kernel patches that improves compability:  https://github.com/driver1998/duo-buildroot-sdk/releases.
 
+- To make MTP support work, please install [uMTP-REsponder](https://github.com/viveris/uMTP-REsponder) as `/usr/bin/umtprd`, and set `/etc/umtprd.conf` based on the [example](./example/umtprd.conf). You should only need to change the storage entry point (`storage` line). \
+If MTP does not work properly on official v1 images, try my fork linked above.

example/umtprd.conf

@@ -0,0 +1,139 @@
+#
+# uMTP Responder config file
+# Must be copied to /etc/umtprd/umtprd.conf
+#
+
+# Loop / daemon mode
+# Set to 1 to don't shutdown uMTPrd when the link is disconnected.
+
+loop_on_disconnect 0
+
+# Force the default UID/GID to use for each storage file operations.
+# Note : When no default UID/GID are specified the umtprd process UID/GID
+#        are used instead.
+
+#default_uid 33
+
+## group: mtp
+#default_gid 33
+
+#
+# umask value for uploaded folders and files
+#
+# Uncomment the umask command line if you want to
+# override the system default umask value for
+# the uploaded folders and files.
+#
+# umask format description :
+#
+# umask 022
+#       ugo
+#
+# u : user/owner part of mask
+# g : group part of mask
+# o : others/not-in-group part of mask
+#
+# Octal digit definition in umask command :
+#
+# 0 : Any permission may be set. (Read, Write, eXecute)
+# 1 : Setting of execute permission is prohibited. (Read and Write)
+# 2 : Setting of write permission is prohibited. (Read and eXecute)
+# 3 : Setting of write and execute permissions is prohibited. (Read only)
+# 4 : Setting of read permission is prohibited. (Write and eXecute)
+# 5 : Setting of read and execute permissions is prohibited. (Write only)
+# 6 : Setting of read and write permissions is prohibited. (eXecute only)
+# 7 : All permissions are prohibited from being set. (No permission)
+#
+
+# Example :
+# User   : Read, Write, eXecute.       (0)
+# Group  : Read, eXecute but no Write. (2)
+# Others : Read, eXecute but no Write, (2)
+
+#umask 022
+
+# Storage command : Create add a storage entry point. Up to 16 entry points supported
+# Syntax : storage "PATH" "NAME" "OPTIONS"
+# Possible store options :
+#     "rw" = read/write access
+#     "ro" = read only
+#     "notmounted" = not mounted by default
+#     "locked" = lock/unlock feature enabled
+
+storage "/mnt/data/disc-emu/isos"  "isos" "rw"
+
+# Set the USB manufacturer string
+
+manufacturer "driver1998"
+
+# Set the USB Product string
+
+product "DiscEmu"
+
+# Set the USB Serial number string
+
+serial "01234567"
+
+# Set the MTP firmware version
+
+firmware_version "Rev A"
+
+# Set the USB interface string. Should be always "MTP"
+
+interface "MTP"
+
+# Set the USB Vendor ID, Product ID and class
+
+usb_vendor_id  0x1D6B # Linux Foundation
+usb_product_id 0x0100 # PTP Gadget
+usb_class 0x6         # Image
+usb_subclass 0x1      # Still Imaging device
+usb_protocol 0x1      #
+
+# Device version
+
+usb_dev_version 0x3008
+
+# inotify support
+# If you want disable the events support (beta), uncomment the following line :
+
+# no_inotify 0x1
+
+# Sync when close
+# Set this option to 0x1 to request all file data to be flushed from the RAM buffer to the
+# internal storage after transfer is completed, this prevents data loss in the case where
+# user un-plugged a non-battery-powered device too soon when there are still buffered data
+# stayed in the RAM
+
+sync_when_close 0x1
+
+#
+# Internal buffers size
+#
+
+# Internal default usb_max_rd_buffer_size and usb_max_wr_buffer_size value set to 0x10000.
+# Internal default read_buffer_cache_size value set to 0x100000.
+# Uncomment the following lines to reduce the buffers sizes to fix USB issues on iMX6 based systems.
+
+# usb_max_rd_buffer_size 0x200      # MAX usb read size. Must be a multiple of 512 and be less than read_buffer_cache_size
+# usb_max_wr_buffer_size 0x200      # MAX usb write size. Must be a multiple of 512.
+# read_buffer_cache_size 0x4000     # Read file cache buffer. Must be a 2^x value.
+
+#
+# USB gadget device driver path
+#
+
+########################################################################
+#
+# -- Generic FunctionFS Mode --
+#
+########################################################################
+
+usb_functionfs_mode 0x1
+
+usb_dev_path   "/dev/usb-ffs/mtp/ep0"
+usb_epin_path  "/dev/usb-ffs/mtp/ep1"
+usb_epout_path "/dev/usb-ffs/mtp/ep2"
+usb_epint_path "/dev/usb-ffs/mtp/ep3"
+
+usb_max_packet_size 0x200