diff --git a/arch/x86/cpu/tangier/acpi.c b/arch/x86/cpu/tangier/acpi.c
index 362e133..8b12813 100644
--- a/arch/x86/cpu/tangier/acpi.c
+++ b/arch/x86/cpu/tangier/acpi.c
@@ -95,7 +95,7 @@
 	si->dma_address_width = 32;
 	si->base_request_line = 0;
 	si->num_handshake_signals = 16;
-	si->max_block_size = 0x20000;
+	si->max_block_size = 0x1ffff;
 
 	return grp->length;
 }