If you have set USE_SAFE_RCW= TRUE, after the "reset_to_debug", but get error, issue is possible related to the HW.
Please kindly test the signals related to the PORESET refer to LS1046A Reference Manual, page 211, Figure 4-1. Power-on reset sequence
And a useful AN, AN12081, RAM Boot using CodeWarrior on LS1046ARDB Application Note
That would help to debug the LS1046A.
https://community.nxp.com/t5/Layerscape-Knowledge-Base/Bring-up-the-LS1046A/ta-p/1575023
Record how to boot up from the eMMC
Enable the on board eMMC
Compile firmware from RCW source file
Program the firmware into the target board (LS1046ARDB)
Some sources may be old, but the steps you could follow.
Anyway, please test the signals to find the root cause would help the customer LS1046A board works reliable.
Any discussion please feel free to let me know.
Thanks