Force the nF bit on.  Usually this is set by the bootrom.  If it is not set,
then the CPU core will run from HCLK instead of FCLK, and performance will
suffer. If you see BogoMIPS of about 1/4 of your CPU clock, try turning this
on; your performance should double.

--- linux-2.6.21.4/arch/arm/mm/proc-arm920.S	2007-06-07 23:27:31.000000000 +0200
+++ linux-2.6.21.4-arm/arch/arm/mm/proc-arm920.S	2007-06-08 22:59:48.000000000 +0200
@@ -395,6 +395,7 @@
 	mrc	p15, 0, r0, c1, c0		@ get control register v4
 	bic	r0, r0, r5
 	orr	r0, r0, r6
+	orr     r0, r0, #0x40000000
 	mov	pc, lr
 	.size	__arm920_setup, . - __arm920_setup