correct linker, add fill pattern for startup

cores/nRF5/linker/gcc_startup_nrf52833.S

@@ -244,6 +244,16 @@ Reset_Handler:
 
 .L_loop1_done:
 
+/* Adafruit fill stack region with pattern 0xADADADAD */
+    ldr     r0, =__StackLimit
+    ldr     r1, =__StackSize
+    ldr     r2, =0xADADADAD
+.L_fill:
+    str     r2, [r0]
+    adds    r0, 4
+    subs    r1, 4
+    bne     .L_fill
+
 /* This part of work usually is done in C library startup code. Otherwise,
  * define __STARTUP_CLEAR_BSS to enable it in this startup. This section
  * clears the RAM where BSS data is located.

cores/nRF5/linker/nrf52833_s140_v7.ld

@@ -14,7 +14,7 @@ MEMORY
    * - Concurrent connection peripheral + central + secure links
    * - Event Len, HVN queue, Write CMD queue
    */
-  RAM (rwx) :  ORIGIN = 0x20006000, LENGTH = 0x20040000 - 0x20006000
+  RAM (rwx) :  ORIGIN = 0x20006000, LENGTH = 0x20020000 - 0x20006000
 }
 
 SECTIONS

programmers.txt

@@ -1,11 +1,17 @@
 #**********************************************
 # Jlink with nrfjprog
 #**********************************************
+
+
 nrfjprog.name=J-Link for Bluefruit nRF52
 nrfjprog.program.tool=bootburn
 nrfjprog.program.cmd={runtime.tools.nrfjprog.path}/nrfjprog
 nrfjprog.program.cmd.windows={runtime.tools.nrfjprog.path}/nrfjprog.exe
 
+# Use nrfjprog in PATH
+#nrfjprog.program.cmd=nrfjprog
+#nrfjprog.program.cmd.windows=nrfjprog.exe
+
 # Burn bootloader pattern
 nrfjprog.program.burn_pattern="{program.cmd}" --program "{bootloader.file}.hex" -f nrf52 --chiperase --reset