Hi @Seongyon_Jeong ,
Thanks for contacting NXP tech support!
Since I don't have RT1020-EVK on my side yet, so far, I tested the operation process using RT1060-EVK locally and it is successful. For the time being, it is provided for your reference.
First, let's make sure that there are two main methods mentioned in this guide.
1. Use MCUXpresso to generate the image linked to the SDRAM and give him an padding header, then use MCUBootUtility to download it to the board;
2. Use MCUXpresso to generate the image without padding header, then use MCUBootUtility to pad it and download it to the board;
I am using the first method.
Step 1: Move the SDRAM to first place;

Step2:Make sure the two macros mentioned in the guide are correct, and check the "link to ram" box;


Step3:Apply the above changes and do the first build; the ld script can only be modified after the build is complete.
Step4: Find the ld script and add the padding header;

Step5:deselect “Manage linker script” in last screenshot. Then you can build again(the second time).

Step 6: The last thing is to generate the s19 file and download the IMAGE using MCUBootUtilitiy;

Note:With this method, there is no need to run "Device Configuration Data" in MCUBootUtility, otherwise it would be a duplicate. However, if you choose the second method to add the header in MCUBootUtility, you need to modify the MCU Memory Map in IDE with appropriate offset.
Best regards,
Gavin