Hi t_kaz,
difference between WDT and POR resets is given in Chapter
System Reset Controller (SRC) Reference Manual.
POR disables (resets) all chip completely, while WDT not.
For example WDT does not disable DDR controler and DDR memories,
so after WDT reset they are reinitialized again.
One can try to disable DDR controler then perform WDT reset.
Also one flush and disable MMU and arm core caches.