This command to load a zImage directly into u-Boot was submitted by
Holger Schurig some time ago.

diff -x ptx-patches -x CVS -urN u-boot/common/cmd_bootz.c u-boot-ptx/common/cmd_bootz.c
--- u-boot/common/cmd_bootz.c	1970-01-01 01:00:00.000000000 +0100
+++ u-boot-ptx/common/cmd_bootz.c	2003-06-14 16:43:44.000000000 +0200
@@ -0,0 +1,101 @@
+/*
+ * (C) Copyright 2003
+ * Holger Schurig, M&N Logistik-Loesungen Online GmbH, <h.schurig@mn...>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * Linux zImage boot support
+ */
+#include <common.h>
+#include <command.h>
+#include <tag.h>
+#include <asm/byteorder.h>
+//#include <asm/setup.h>
+
+#define DEBUG
+ 
+#ifdef CONFIG_SHOW_BOOT_PROGRESS
+# include <status_led.h>
+# define SHOW_BOOT_PROGRESS(arg)        show_boot_progress(arg)
+#else
+# define SHOW_BOOT_PROGRESS(arg)
+#endif
+
+
+#define CONFIG_KERNEL_RAM_BASE 0x40000
+
+int do_bootz (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+    DECLARE_GLOBAL_DATA_PTR;
+
+    ulong addr = 0x40000;
+    ulong initrd_start = 0;
+    ulong initrd_end = 0;
+    ulong data;
+    void (*theKernel)(int zero, int arch, struct tag *params);
+    bd_t *bd = gd->bd;
+#ifdef CONFIG_CMDLINE_TAG
+    char *commandline = getenv("bootargs");
+#endif
+    addr = simple_strtoul(argv[1], NULL, 16);
+
+    theKernel = (void (*)(int, int, struct tag*))addr;
+
+    SHOW_BOOT_PROGRESS (14);
+
+#ifdef DEBUG
+    printf ("## Transferring control to Linux (at address %08lx) ...\n",
+            (ulong)theKernel);
+#endif
+
+#if defined (CONFIG_SETUP_MEMORY_TAGS) || \
+    defined (CONFIG_CMDLINE_TAG) || \
+    defined (CONFIG_INITRD_TAG) || \
+    defined (CONFIG_VFD)
+    setup_start_tag(bd);
+#ifdef CONFIG_SETUP_MEMORY_TAGS
+    setup_memory_tags(bd);
+#endif
+#ifdef CONFIG_CMDLINE_TAG
+    setup_commandline_tag(bd, commandline);
+#endif
+#ifdef CONFIG_INITRD_TAG
+    setup_initrd_tag(bd, initrd_start, initrd_end);
+#endif
+#if 0
+    setup_ramdisk_tag(bd);
+#endif
+#if defined (CONFIG_VFD)
+    setup_videolfb_tag(gd);
+#endif
+    setup_end_tag(bd);
+#endif
+
+    /* we assume that the kernel is in place */
+    printf("\nStarting kernel ...\n\n");
+
+    cleanup_before_linux();
+
+    theKernel(0, bd->bi_arch_number, params);
+
+    printf("ERROR: we should never come to this place ...\n\n");
+    return 0;
+}