This is most-likely not complete:
+autostart
+ If set to "yes" (actually any string starting with 1, y, Y, t, or T) an
+ image loaded with one of the commands listed below will be automatically
+ started by internally invoking the bootm command.
+
+ * bootelf - Boot from an ELF image in memory
+ * bootp - boot image via network using BOOTP/TFTP protocol
+ * dhcp - boot image via network using DHCP/TFTP protocol
+ * diskboot - boot from ide device
+ * nboot - boot from NAND device
+ * nfs - boot image via network using NFS protocol
+ * rarpboot - boot image via network using RARP/TFTP protocol
+ * scsiboot - boot from SCSI device
+ * tftpboot - boot image via network using TFTP protocol
+ * usbboot - boot from USB device
+
+ If the environment variable autostart is not set to a value starting with
+ 1, y, Y, t, or T, an image passed to the "bootm" command will be copied to
+ the load address (and eventually uncompressed), but NOT be started.
+ This can be used to load and uncompress arbitrary data.
+
baudrate
Used to set the baudrate of the UART - it defaults to CONFIG_BAUDRATE (which
defaults to 115200).
configuration from the BOOTP server, but not try to
load any image.
-autostart
- if set to "yes", an image loaded using the "bootp", "dhcp",
- "rarpboot", "tftpboot" or "diskboot" commands will
- be automatically started (by internally calling
- "bootm")
-
- If unset, or set to "1"/"yes"/"true" (case insensitive, just the first
- character is enough), a standalone image
- passed to the "bootm" command will be copied to the load address
- (and eventually uncompressed), but NOT be started.
- This can be used to load and uncompress arbitrary
- data.
-
fdt_high
if set this restricts the maximum address that the
flattened device tree will be copied into upon boot.