Please refer to the following procedure to execute secure boot.
First you need to write OTPMK to fuse array under u-boot.
Write OTPMK fuse values on shadow registers
mw.l 1e80234 a29a0b2c
mw.l 1e80238 2c8cd201
mw.l 1e8023c 84027ca8
mw.l 1e80240 8e13c7b9
mw.l 1e80244 a0b9d347
mw.l 1e80248 50ef2622
mw.l 1e8024c 98a92efd
mw.l 1e80250 ed53d1c3
Check OTPMK_ZERO and OTPMK_SYNDROME as 0 in SecMon_HP Status Register
md 1e90014
80000900
Check SFP_SVHESR no parity error.
md 1e80024
00000000
Permanently write OTPMK from the mirror registers into the fuse array
mw 1e80020 0x02000000
After program secure boot image on the custom board, you need to reset the target board, connect CodeWarrior CCS to the target board to program SRKH mirror registers in CodeWarrior CCS environment
ccs::config_server 0 10000
ccs::config_chain {ls1043a dap sap2}
display ccs::get_config_chain
#Check Initial SNVS State and Value in SCRATCH Registers
ccs::display_mem <dap position> 0x1e90014 4 0 4
ccs::display_mem <dap position> 0x1ee0200 4 0 4
#Wrie the SRK Hash Value in Mirror Registers
ccs::write_mem <dap position> 0x1e80254 4 0 <SRKH1>
ccs::write_mem <dap position> 0x1e80258 4 0 <SRKH2>
ccs::write_mem <dap position> 0x1e8025c 4 0 <SRKH3>
ccs::write_mem <dap position> 0x1e80260 4 0 <SRKH4>
ccs::write_mem <dap position> 0x1e80264 4 0 <SRKH5>
ccs::write_mem <dap position> 0x1e80268 4 0 <SRKH6>
ccs::write_mem <dap position> 0x1e8026c 4 0 <SRKH7>
ccs::write_mem <dap position> 0x1e80270 4 0 <SRKH8>
#Get the Core Out of Boot Hold-Off
ccs::write_mem <dap position> 0x1ee00e4 4 0 0x00000001
Please refer to "3. Deploy Secure Boot Images to the Target and Write SRKH Mirror Register" section in https://community.nxp.com/t5/Qonverge-Knowledge-Base/Setting-up-Secure-Boot-on-PBL-Based-Platforms-i... for details.
Please refer to "6.1.1.5 Procedure to run secure boot" in LSDK 20.12 user manual.