Bug#825171: Acknowledgement ([powerpc] Some USB device are not (easily) supported for d-i)

[Mathieu Malaterre <malat@debian.org>]

Just for reference here is how one can mount a FAT32 USB key during a
Debian installation on powerpc. This is needed for example when one
wants to store the `dmesg` output during a d-i installation. Since
isofs is stricly a read-only system, one cannot use the USB key used
during the installation, instead a FAT32 key seems like a good option.

For some reason the linux kernel version used during installation does
not have vfat module (`modprobe vfat` → fail ! Thus `mount` does not
work). Instead one should:

[Ctrl+2, search for modules from the iso]
$ cp fat-modules-4.5.0-2-powerpc-di_4.5.3-2_powerpc.udeb /tmp
$ cd /tmp
$ ar -x fat-modules-4.5.0-2-powerpc-di_4.5.3-2_powerpc.udeb
$ xzcat data.tar.xz > data.tar
$ tar xf data.tar
$ cd /tmp/lib/modules/4.5.0-2-powerpc/kernel/fs/fat
$ insmod fat.ko
$ insmod vfat.ko
$ cd /tmp/lib/modules/4.5.0-2-powerpc/kernel/fs/nls
$ insmod nls_cp437.ko
$ insmod nls_utf8.ko

Now finally mount works:

$ mount /dev/sdb /tmp/bla

cheers