nanopc t4: fix sdram unstable

Set sdram frequency to 1600MHz and switch to blobless

config/boards/nanopct4.csc

@@ -9,6 +9,6 @@ FULL_DESKTOP="yes"
 ASOUND_STATE="asound.state.rt5651"
 BOOT_LOGO="desktop"
 BOOT_FDT_FILE="rockchip/rk3399-nanopc-t4.dtb"
-BOOT_SCENARIO="spl-blobs"
+BOOT_SCENARIO="blobless"
 SRC_EXTLINUX="yes"
 SRC_CMDLINE="console=ttyS2,1500000 console=tty0"

patch/u-boot/u-boot-rockchip64-v2022.04/rk3399-nanopc-t4-use-1600MHz-sdram-configuration.patch

@@ -0,0 +1,25 @@
+From 7e982e4a89d1f2e23b121c2db5386dc348f0e52b Mon Sep 17 00:00:00 2001
+From: Lu jicong <[email protected]>
+Date: Wed, 29 Jan 2025 19:46:03 +0800
+Subject: [PATCH] nanopc-t4: use 1600MHz sdram configuration
+
+Some boards are unstable at 1866MHz configuration
+Switch to 1600MHz to avoid unstable problems
+This is also consistent with stock frequency
+---
+ arch/arm/dts/rk3399-nanopc-t4-u-boot.dtsi | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/arch/arm/dts/rk3399-nanopc-t4-u-boot.dtsi b/arch/arm/dts/rk3399-nanopc-t4-u-boot.dtsi
+index 17201bcf41..8b6c9059ab 100644
+--- a/arch/arm/dts/rk3399-nanopc-t4-u-boot.dtsi
++++ b/arch/arm/dts/rk3399-nanopc-t4-u-boot.dtsi
+@@ -4,4 +4,4 @@
+  */
+
+ #include "rk3399-nanopi4-u-boot.dtsi"
+-#include "rk3399-sdram-lpddr3-samsung-4GB-1866.dtsi"
++#include "rk3399-sdram-lpddr3-4GB-1600.dtsi"
+-- 
+2.39.5
+

patch/u-boot/u-boot-rockchip64/rk3399-nanopc-t4-use-1600MHz-sdram-configuration.patch

@@ -0,0 +1,25 @@
+From 7e982e4a89d1f2e23b121c2db5386dc348f0e52b Mon Sep 17 00:00:00 2001
+From: Lu jicong <[email protected]>
+Date: Wed, 29 Jan 2025 19:46:03 +0800
+Subject: [PATCH] nanopc-t4: use 1600MHz sdram configuration
+
+Some boards are unstable at 1866MHz configuration
+Switch to 1600MHz to avoid unstable problems
+This is also consistent with stock frequency
+---
+ arch/arm/dts/rk3399-nanopc-t4-u-boot.dtsi | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/arch/arm/dts/rk3399-nanopc-t4-u-boot.dtsi b/arch/arm/dts/rk3399-nanopc-t4-u-boot.dtsi
+index 17201bcf41..8b6c9059ab 100644
+--- a/arch/arm/dts/rk3399-nanopc-t4-u-boot.dtsi
++++ b/arch/arm/dts/rk3399-nanopc-t4-u-boot.dtsi
+@@ -4,4 +4,4 @@
+  */
+
+ #include "rk3399-nanopi4-u-boot.dtsi"
+-#include "rk3399-sdram-lpddr3-samsung-4GB-1866.dtsi"
++#include "rk3399-sdram-lpddr3-4GB-1600.dtsi"
+-- 
+2.39.5
+