diff --git a/src/soc/mediatek/mt8186/emi.c b/src/soc/mediatek/mt8186/emi.c
index 48a7b3ef07..6e2544185e 100644
--- a/src/soc/mediatek/mt8186/emi.c
+++ b/src/soc/mediatek/mt8186/emi.c
@@ -5,11 +5,30 @@
  * Chapter number: 4.8
  */
 
+#include <assert.h>
+#include <cbmem.h>
+#include <commonlib/bsd/mem_chip_info.h>
 #include <soc/emi.h>
 
 size_t sdram_size(void)
 {
-	return (size_t)4 * GiB;
+	const struct mem_chip_info *mc;
+	size_t size = 0;
+
+	if (ENV_ROMSTAGE) {
+		size = mtk_dram_size();
+		printk(BIOS_INFO, "dram size (romstage): %#lx\n", size);
+		return size;
+	}
+
+	mc = cbmem_find(CBMEM_ID_MEM_CHIP_INFO);
+	assert(mc);
+
+	for (unsigned int i = 0; i < mc->num_channels; ++i)
+		size += mc->channel[i].density;
+
+	printk(BIOS_INFO, "dram size: %#lx\n", size);
+	return size;
 }
 
 void mt_set_emi(struct dramc_param *dparam)