+
+Booting from an SD card on RK3288 with TPL
+==========================================
+
+Since the size of SPL can't be exceeded 0x8000 bytes in RK3288, it is not possible add
+new SPL features like Falcon mode or etc.
+
+So introduce TPL so-that adding new features to SPL is possible because now TPL should
+run minimal with code like DDR, clock etc and rest of new features in SPL.
+
+As of now TPL is added on Vyasa-RK3288 board.
+
+To write an image that boots from an SD card (assumed to be /dev/mmcblk0):
+
+ ./tools/mkimage -n rk3288 -T rksd -d ./tpl/u-boot-tpl.bin out &&
+ cat ./spl/u-boot-spl-dtb.bin >> out &&
+ sudo dd if=out of=/dev/mmcblk0 seek=64 &&
+ sudo dd if=u-boot-dtb.img of=/dev/mmcblk0 seek=16384
+
+Booting from an SD card on RK3188
+=================================
+
+For rk3188 boards the general storage onto the card stays the same as
+described above, but the image creation needs a bit more care.
+
+The bootrom of rk3188 expects to find a small 1kb loader which returns
+control to the bootrom, after which it will load the real loader, which
+can then be up to 29kb in size and does the regular ddr init. This is
+handled by a single image (built as the SPL stage) that tests whether
+it is handled for the first or second time via code executed from the
+boot0-hook.
+
+Additionally the rk3188 requires everything the bootrom loads to be
+rc4-encrypted. Except for the very first stage the bootrom always reads
+and decodes 2kb pages, so files should be sized accordingly.
+
+# copy tpl, pad to 1020 bytes and append spl
+tools/mkimage -n rk3188 -T rksd -d spl/u-boot-spl.bin out
+
+# truncate, encode and append u-boot.bin
+truncate -s %2048 u-boot.bin
+cat u-boot.bin | split -b 512 --filter='openssl rc4 -K 7C4E0304550509072D2C7B38170D1711' >> out
+
+