Why the R36S Plus Stops at 1.30 GHz (Same RK3326 — Missing 1.51 GHz in the Device Tree)

The R36S Plus uses the same Rockchip RK3326 as the classic R36S. Heavy PSP still felt slower on Plus units we opened — not because the silicon is weaker, but because the 720×720 panel device tree never lists 1.51 GHz. Here is how we spotted that, what we change in the workshop, and what you should not do (swap the whole DTB and brick the screen).

The one-paragraph truth

OTP on the Plus unit we measured still said RK3326. GPU already tops out at 520 MHz on both trees. CPU on Plus stopped at 1.30 GHz because the live OPP table only had 1008 / 1200 / 1248 / 1296 MHz. The RG351MP kernel DTB sitting on the same SD already contained opp-1512000000 at the same 1.35 V the Plus uses at 1.30 GHz. So this is a missing table row, not a voltage overclock.

Unlocking it does not make Ghost of Sparta run at 60 FPS. It gives the chip the same top gear the 3.5" units already had. For the PSP settings on top, use how to push the R36S to the max for heavy PSP titles.

How to tell you are on the Plus tree

Enable Remote Services (Options → Enable Remote Services) and SSH as ark / ark, or open Filebrowser at http://YOUR-IP/. Then:

cat /sys/class/graphics/fb0/virtual_size
# Plus we measured: 720,720

cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies
# Plus stock: 1008000 1200000 1248000 1296000
# Classic R36S / RG351MP tree often already includes 1512000

grep dtb /boot/boot.ini
# Plus: load mmc 1:1 ... rk3326-r36plus-linux.dtb

If 1512000 is already in the available list, you do not need this DTB graft. You still may want the thermal unlock in the max-settings article — God of War will sit at 90–105°C and the stock 70°C IPA trip will clip you anyway.

What we change in the workshop

1. Copy the live DTB to /boot/rk3326-r36plus-linux.dtb.pre-1512 (restore file).
2. Graft opp-1512000000 from rg351mp-kernel.dtb into the Plus CPU OPP table (same microvolts as 1296 MHz, PVTM bin 1).
3. Reboot. Confirm scaling_available_frequencies includes 1512000 and the framebuffer is still 720×720.
4. Stop perfmax from forcing 1296000 on every game launch — after the graft, that script can silently cap you again. Use cpuinfo_max_freq instead.

This is a device-tree edit. A bad blob will not boot a picture. If you are not comfortable restoring a file on the BOOT partition from a PC card reader, do not do this at home — book the free video call and we will show a tuned unit instead.

Restore if the screen is wrong

sudo cp /boot/rk3326-r36plus-linux.dtb.pre-1512 /boot/rk3326-r36plus-linux.dtb
sudo reboot

If SSH is dead, pull the SD, mount the FAT BOOT partition on a PC, and copy the .pre-1512 file back over rk3326-r36plus-linux.dtb.

Heat after the boost

At 1.51 GHz in Ghost of Sparta the Plus SoC we logged climbed from ~90°C to the IPA trip. GPU sat near 100°C. Clocks then oscillated (1.51 GHz ↔ ~1.01 GHz, GPU 520 ↔ 400 MHz) until the game was closed. That is expected in a sealed 4" shell with no fan.

Stock critical shutdown stays 115°C. Raising the 70°C trip so the extra OPP is actually used is a separate step — details and the 105°C workshop setting are in the max settings guide. Keep vents clear. Stop if the back is uncomfortable to hold.