diff --git a/arch/sandbox/Kconfig b/arch/sandbox/Kconfig
index 2a08533..65f988e 100644
--- a/arch/sandbox/Kconfig
+++ b/arch/sandbox/Kconfig
@@ -15,6 +15,16 @@
 	select PHYS_64BIT
 	select HOST_64BIT
 
+config SANDBOX_RAM_SIZE_MB
+	int "RAM size in MiB"
+	default 128
+	range 64 4095 if !SANDBOX64
+	range 64 268435456 if SANDBOX64
+	help
+	  Memory size of the sandbox in MiB. The default value is 128 MiB.
+	  The minimum value is 64 MiB. The maximum value is 4095 MiB for the
+	  32bit sandbox.
+
 config SANDBOX_SPL
 	bool "Enable SPL for sandbox"
 	select SUPPORT_SPL
diff --git a/arch/sandbox/include/asm/state.h b/arch/sandbox/include/asm/state.h
index 705645d..1bfad30 100644
--- a/arch/sandbox/include/asm/state.h
+++ b/arch/sandbox/include/asm/state.h
@@ -73,7 +73,7 @@
 	char **argv;			/* Command line arguments */
 	const char *jumped_fname;	/* Jumped from previous U_Boot */
 	uint8_t *ram_buf;		/* Emulated RAM buffer */
-	unsigned int ram_size;		/* Size of RAM buffer */
+	unsigned long ram_size;		/* Size of RAM buffer */
 	const char *ram_buf_fname;	/* Filename to use for RAM buffer */
 	bool ram_buf_rm;		/* Remove RAM buffer file after read */
 	bool write_ram_buf;		/* Write RAM buffer on exit */
diff --git a/include/configs/sandbox.h b/include/configs/sandbox.h
index 1a981a7..0353a19 100644
--- a/include/configs/sandbox.h
+++ b/include/configs/sandbox.h
@@ -47,8 +47,11 @@
 #define CONFIG_PHYSMEM
 
 /* Size of our emulated memory */
+#define SB_CONCAT(x, y) x ## y
+#define SB_TO_UL(s) SB_CONCAT(s, UL)
 #define CONFIG_SYS_SDRAM_BASE		0
-#define CONFIG_SYS_SDRAM_SIZE		(128 << 20)
+#define CONFIG_SYS_SDRAM_SIZE \
+		(SB_TO_UL(CONFIG_SANDBOX_RAM_SIZE_MB) << 20)
 #define CONFIG_SYS_MONITOR_BASE	0
 
 #define CONFIG_SYS_BAUDRATE_TABLE	{4800, 9600, 19200, 38400, 57600,\