diff -uNr linux/drivers/block/rd.c linux-2.4.4/drivers/block/rd.c
--- linux/drivers/block/rd.c	Fri Feb  9 13:30:22 2001
+++ linux-2.4.4/drivers/block/rd.c	Mon May  7 14:04:15 2001
@@ -47,6 +47,7 @@
 #include <linux/minix_fs.h>
 #include <linux/ext2_fs.h>
 #include <linux/romfs_fs.h>
+#include <linux/cramfs_fs.h>
 #include <linux/fs.h>
 #include <linux/kernel.h>
 #include <linux/hdreg.h>
@@ -469,10 +470,11 @@
 int __init
 identify_ramdisk_image(kdev_t device, struct file *fp, int start_block)
 {
-	const int size = 512;
+	const int size = 1024;
 	struct minix_super_block *minixsb;
 	struct ext2_super_block *ext2sb;
 	struct romfs_super_block *romfsb;
+	struct cramfs_super *cramfsb, *cramfsb2;
 	int nblocks = -1;
 	unsigned char *buf;

@@ -483,6 +485,8 @@
 	minixsb = (struct minix_super_block *) buf;
 	ext2sb = (struct ext2_super_block *) buf;
 	romfsb = (struct romfs_super_block *) buf;
+	cramfsb = (struct cramfs_super *) buf;
+	cramfsb2 = (struct cramfs_super *) (&buf[512]);
 	memset(buf, 0xe5, size);

 	/*
@@ -515,6 +519,41 @@
 		goto done;
 	}

+	/* cramfs also at block zero */
+	/* (superblock can also live at 512-byte offset in block zero) */
+	if ((cramfsb->magic == CRAMFS_MAGIC &&
+		memcmp(cramfsb->signature, CRAMFS_SIGNATURE,
+                                       sizeof(cramfsb->signature)) == 0) ||
+	    ((cramfsb = cramfsb2)  &&  cramfsb2->magic == CRAMFS_MAGIC &&
+		memcmp(cramfsb2->signature, CRAMFS_SIGNATURE,
+                                       sizeof(cramfsb2->signature)) == 0)) {
+
+		printk(KERN_NOTICE
+		       "RAMDISK: cramfs filesystem found at block %d\n",
+		       start_block);
+
+		/* cramfs probably has a different blocksize--adjust the
+		   ramdisk's block size to accomodate */
+		/* FIXME: should have a way to determine the cramfs
+		          blocksize (if it's going to be variable.....) */
+		if (rd_blocksize != PAGE_CACHE_SIZE) {
+			int i;
+
+			rd_blocksize = PAGE_CACHE_SIZE;
+			for (i = 0; i < NUM_RAMDISKS; i++) {
+				rd_hardsec[i] = rd_blocksize;
+				rd_blocksizes[i] = rd_blocksize;
+			}
+			printk(KERN_NOTICE
+				"RAMDISK: overriding ramdisk block size to %d for cramfs filesystem\n",
+				rd_blocksize);
+		}
+		/* Note: even if ramdisk blocksize is changed, nblocks is still
+                   calculated using 1k blocksize for the INITRD device */
+		nblocks = (cramfsb->size+BLOCK_SIZE-1)>>BLOCK_SIZE_BITS;
+		goto done;
+	}
+
 	/*
 	 * Read block 1 to test for minix and ext2 superblock
 	 */