Precompiled blinky .hex works, my compiled does not

Question

Hi, 
 
 I've installed arm-gcc and the dev kit, I've tried several different versions. 
 
 I got it to compile the examples just fine. I can compile the example in examples/peripheral/blinky/pca10040/blank/armgcc/ 
 
 I built my own dev board, and the problem is: using nrfjprog I can flash the precompiled example and it blinks the LED, but my compiled one does not. I don't understand exactly what's happening. 
 I'm using nRF5_SDK_14.2.0_17b948a and gcc gcc-arm-none-eabi-7-2017-q4-major on Ubuntu Linux x64_64. 
 
 My dev board is "rudimentary" but it contains a LED on GPIO20 and it flashes when the precompiled example runs. I can connect using nrfjprog and send new firmware. I am using a cheapo third party j-link cable. 
 One other thing - the LED blinks much slower (maybe about 4x slower) than it should. This might be because the chip is not running at the same speed as the real pca10040 dev board, I'm using a Bluenor BT832 module ("dead bug" soldered on a prototype strip-board with some LEDs and a reset button)

MarkR42 · Answer

OK, I think I *MAY* have cracked it. 
 
 I think I've actually got a nrf52810 instead of the 32 version. This has less RAM, so it crashes when trying to use the stack which is at 64k, but it only has 24k of ram. 
 
 For reasons which are unclear, the precompiled blinky example starts its stack pointer lower down, so it works! 
 I'm reading the specs, I think I ordered the BT832A module which has a 52810. Of course I can't see the writing on the chip, because it's under a tin lid like most of these modules.