Bug#950587: Also impacted by this bug.

[Arnaud Mouiche <amouiche.dev@gmail.com>]

Due to wrong cmdline parsing, the installer failed to setup debian 
properly for an ARM device where MTD partitions are provided by bootloader.

The bootloader pass this cmdline:

cmdlinepart.mtdparts="spi0.0:512k@0(uboot)ro,3M@0x100000(Kernel),12M@0x400000(RootFS1),2M@0x200000(Kernel_legacy),256k@0x80000(U-Boot 
Config),256k@0xc0000(NAS Config)"

The debian installer creates /etc/modprobe.d/local.conf

    # Local module settings
    # Created by the Debian installer

    options cmdlinepart 
mtdparts="spi0.0:512k@0(uboot)ro,3M@0x100000(Kernel),12M@0x400000(RootFS1),2M@0x200000(Kernel_legacy),256k@0x80000(U-Boot

which is rubbish...

Regards,
Arnaud