diff --git a/arch/arm/mach-at91/spl_atmel.c b/arch/arm/mach-at91/spl_atmel.c
index ef745c9..85290be 100644
--- a/arch/arm/mach-at91/spl_atmel.c
+++ b/arch/arm/mach-at91/spl_atmel.c
@@ -44,7 +44,15 @@
 #endif
 
 	tmp = readl(&pmc->mor);
+/*
+ * some boards have an external oscillator with driving.
+ * in this case we need to disable the internal SoC driving (bypass mode)
+ */
+#if defined(CONFIG_SPL_AT91_MCK_BYPASS)
+	tmp |= AT91_PMC_MOR_OSCBYPASS;
+#else
 	tmp &= ~AT91_PMC_MOR_OSCBYPASS;
+#endif
 	tmp &= ~AT91_PMC_MOR_KEY(0xff);
 	tmp |= AT91_PMC_MOR_KEY(0x37);
 	writel(tmp, &pmc->mor);