- * scriptaddr can be pretty much anywhere that doesn't conflict with something
- * else. Put it low in memory to avoid conflicts.
+ * I suspect address 0 is used as the SMP pen on the RPi2, so avoid this.
+ *
+ * fdt_addr_r simply shouldn't overlap anything else. However, the RPi's
+ * binary firmware loads a DT to address 0x100, so we choose this address to
+ * match it. This allows custom boot scripts to pass this DT on to Linux
+ * simply by not over-writing the data at this address. When using U-Boot,
+ * U-Boot (and scripts it executes) typicaly ignore the DT loaded by the FW
+ * and loads its own DT from disk (triggered by boot.scr or extlinux.conf).