AM5728: WDT reset insesitive register.

Part Number:AM5728

I need to store somewhere a value, which would survive a WDT reset. Is there any register meant to store a value throughout WDT reset? Even one bit would help!
I tried a few registers, specified as warm reset insensitive, but meant for other purposes and unused by our project. None of them seem to actually retain its value after WDT reset.
I tried CM_SSC_DELTAMSTEP_DPLL_GPU (0x4A0052F0), CM_CLKSEL_DPLL_IVA (0x4A0051AC), PRM_DEBUG_CFG1 (0x4AE060E4) and others.

I am checking these registers at the very beginning of SBL's main(), before they are overwritten by board initialization functions. They are always 0 there.

Alternative would be to create a file on disk, but this adds so much complexity.