What Is MaskROM Mode? Rockchip Recovery and Loader Mode Explained

Every Rockchip SoC contains a small, read-only program called the BootROM. On power-up it looks for a valid bootloader on the boot media. If it finds none, or if you force it, it exposes a USB device and waits for a host to send it code. That USB state is MaskROM mode.

Because the BootROM cannot be erased, you can almost always recover a Rockchip board, even with completely empty or corrupted flash.

MaskROM vs Loader mode

How to enter MaskROM mode

1. Board has a MaskROM button: hold it, apply power (or press reset), release after about 2 seconds.
2. No button: short the eMMC clock test point (or the SPI flash CLK/CS) to GND while powering on. The BootROM fails to read flash and falls back to USB. Remove the short straight after power-up.
3. Blank board: a board with empty flash boots straight into MaskROM.

Connect the board's USB OTG port (often a USB-C port marked OTG or the upper USB 3 port on some SBCs) to your PC.

Confirming the mode

On Linux:

$ lsusb | grep 2207
Bus 001 Device 012: ID 2207:350b Fuzhou Rockchip Electronics Company

$ rkdeveloptool ld
DevNo=1	Vid=0x2207,Pid=0x350b,LocationID=104	Maskrom

The vendor ID is always 0x2207. The product ID identifies the SoC family. Common values are 0x350b for RK3588/RK3588S, 0x350a for RK3568/RK3566 and 0x330c for RK3399. On Windows, RKDevTool shows "Found One MASKROM Device".

Flashing from MaskROM

# 1. Load the SPL loader into RAM (it initialises DDR)
rkdeveloptool db rk3588_spl_loader_v1.xx.xxx.bin

# 2. Write a raw disk image from sector 0
rkdeveloptool wl 0 your-image.img

# 3. Reboot
rkdeveloptool rd

The loader file comes from rkbin or from your board vendor. It must match the SoC. For update.img firmware packages, use RKDevTool on Windows or upgrade_tool uf update.img on Linux.

Troubleshooting

• No USB device appears: wrong USB port (it must be the OTG port), a charge-only cable, or the board still boots from SD. Remove the SD card.
• Device appears then disconnects: weak power. Use a proper supply, not the PC USB port alone, for RK3588 boards.
• "Creating Comm Object failed": permissions. Add a udev rule (see our rkdeveloptool guide).

Designing your own board? Always bring out a MaskROM button (or test pad) and the debug UART. It costs almost nothing and saves days in bring-up and in the field.