SDK 12.3.0 DFU service not work

Question

Hi Forums, 
 I work 51822 custom board. 
 I try to add Buttonless DFU so I test the "experimental_ble_app_buttonless_dfu" compile is good. 
 But flash to the board can't find DFU service on NRF Connect tool. 
 I search online then find most discuss SDK 12.1.0 So I download SDK 12.1.0 build "experimental_ble_app_buttonless_dfu" then flash to board. Magic! It's fine. 
 I think is strange so try test SDK 12.2.0 . Sadly not worked. 
 What's different between SDK 12.1.0 ~ SDK 12.2.0 make ble dfu service not work? 
 Is any suggestion to fix this on SDK 12.3.0? 
 Thanks for any information.

bjorn-spockeli · Accepted Answer

There is a bootloader settings section that is missing in the linker script, so if you modify the ble_app_buttonless_dfu_gcc_nrf51.ld to the following you should be able to get the buttonless example to run. 
 /* Linker script to configure memory regions. */

SEARCH_DIR(.)
GROUP(-lgcc -lc -lnosys)

MEMORY
{
 FLASH (rx) : ORIGIN = 0x1b000, LENGTH = 0x24000
 RAM (rwx) : ORIGIN = 0x20001ff8, LENGTH = 0x6008
 BOOTLOADER_SETTINGS (rw) : ORIGIN = 0x0003F000, LENGTH = 0x1000
}

SECTIONS
{
 .bootloaderSettings(NOLOAD) :
 {

 } > BOOTLOADER_SETTINGS
 
 .fs_data :
 {
 PROVIDE(__start_fs_data = .);
 KEEP(*(.fs_data))
 PROVIDE(__stop_fs_data = .);
 } > RAM
 .pwr_mgmt_data :
 {
 PROVIDE(__start_pwr_mgmt_data = .);
 KEEP(*(.pwr_mgmt_data))
 PROVIDE(__stop_pwr_mgmt_data = .);
 } > RAM
} INSERT AFTER .data;

INCLUDE "nrf5x_common.ld"