在unstabl引导问题e voltage environment

Hi
We have some problem with boot sequence in unstable voltage environment.
1) Our FW is uploaded from Flash via SPI and we don't use OTP at all.
As part of system test we generate brief voltage drop during FW upload from Flash to RAM.
This voltage drop is not so deep to reset MCU, but deep enough to disrupt FW upload.
According to Figure. 1 from "AN-B-001 - DA1458x Booting from serial
interfaces" watchdog should be enabled at the end of boot sequence. So, we expected that after an unsuccessful attempt of FW upload watchdog timer will expired and new boot sequence will start by ROM.
But, in fact, DA14580 just stay stuck. It back to normal functionality after power reset or after set RST pin to high.

2) To avoid voltage drops due loose battery contact we decide to add a supervisor IC that connected to RST pin. Generally, it solves the problem, but still there is a problematic scenario.
If there are 2 consequences voltage spikes ( in fact 2 resets ) and interval between them is less then about 0.5 seconds, DA14580 will stay stuck. It back to normal functionality after power reset ONLY.
Could you help us?