3 HS Device Flashing With Multiple Memory Boot Mode

If the UART interface is not supported and there are other memory boot modes besides OSPI boot mode, like SD boot mode, below steps required for flashing:

1. Install the keywriter addon package in SDK and build keywriter with customer key, find the command and log as shown below.

   $make keywriter_img
   #......
   # SBL image ~/ti-processor-sdk-rtos-j721e-evm-07_01_00_11/pdk_jacinto_07_01_00_45/packages/ti/boot/sbl/example/k3MulticoreApp/binary/keywriter_img_j721e_release.tiimage created.

2. In SD boot mode, power on the HS-FS device and run keywriter application, convert the device to HS-SE device, find log as shown below if the key programing is completed.

   #Keywriter Revision: 01.00.00.00 (Mar  7 2021 - 20:15:01)
   # OTP Keywriter ver: 20.8.5-w2020.23-am64x-14-g7409e
   #Beginning key programming sequence 
   #Taking OTP configuration from 0x41c7e000
   #Debug response: 0x0
   #Key programming is complete

3. Sign and encrypt the u-boot binary in customer HSM first, meanwhile also Sign and encrypt all binaries that will flash into OSPI, then copy those binaries to SD card boot partition.
4. Insert the SD card and power cycle the board, stop in u-boot command phase, and flash all the binaries to OSPI from SD card by using the following command.

   Hit any key to stop autoboot:  0 
   => 
   => sf probe
   SF: Detected s28hs512t with page size 256 Bytes, erase size 256 KiB, total 64 MiB
   => mmc dev 1
   switch to partitions #0, OK
   mmc1 is current device
   => fatload mmc 1 ${loadaddr} sbl_ospi_img_mcu1_0_release.tiimage
   231444 bytes read in 5 ms (44.1 MiB/s)
   => sf update ${loadaddr} 0x0 0x40000
   device 0 offset 0x0, size 0x40000
   262144 bytes written, 0 bytes skipped in 1.331s, speed 201225 B/s
   =>

5. Switch to OSPI boot mode and power cycle the board.
6. Repeated the step 3 to approximately 5 to update the system binary.

Same procedure also applies to other memory boot modes, only need to stop in u-boot phase and flash OSPI.