How can I use DFU with peripherals/blinky?

[gfmoore]

I have flashed DFU OTA bootlaoder to my nRF82540 DK. (C:\nRF5_SDK_17.0.2_d674dde\examples\dfu\secure_bootloader\pca10056_s140_ble_debug)

It shows the two LEDs 1 and 2.

I can flash ble_blinky. It shows LEDs 1 and 3 when flashing. It works.

BUT So I can get some understanding of what is going on I would like to flash plain old blink to the device using the OTA.

I change the blink *.ld file from

MEMORY
{
FLASH (rx) : ORIGIN = 0x1000, LENGTH = 0xff000
RAM (rwx) : ORIGIN = 0x20000008, LENGTH = 0x3fff8
}

to

MEMORY
{
FLASH (rx) : ORIGIN = 0x27000, LENGTH = 0xff000
RAM (rwx) : ORIGIN = 0x20000008, LENGTH = 0x3fff8
}

So that the application is now above the softdevice. It all looks fine, but it doesn't work.

So how do things work. I'm assuming that somewhere there is a jump to the address where the blinky app is loaded (at 0x27000?) and then blinky runs.

I'm guessing that my ignorance is going to give me a heart attack at some point. 

Is there a document that explains for newbies how all of this hangs together?

Gordon

(In my research I've seen references to a define for APPLICATION_START_ADDRESS or something similar, but I can't find it. It may have been an old sdk?)

Here is my memory map

[gfmoore]

So could I ask:

Is there  any conflict with using --debug-mode and --application-version=1? or does --debug-mode trump --application-version?

Where is the idiot's guide reference to how the boot process works from master boot to bootloader to application. Apart from positioning an application properly in memory space are there any flags, defines apart from the memory origin in the *.ld linker file?