[PATCH v5 2/9] rockchip: doc: add mask ROM mode text

[Johan Jonker <jbx6244@gmail.com>]

Add text that explains how to get into mask ROM mode.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---

Changed V5:
reword
---
 doc/board/rockchip/rockchip.rst | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/doc/board/rockchip/rockchip.rst b/doc/board/rockchip/rockchip.rst
index de2df3046e28..af6c08c46636 100644
--- a/doc/board/rockchip/rockchip.rst
+++ b/doc/board/rockchip/rockchip.rst
@@ -325,6 +325,27 @@ To build rk3588 boards:
         make evb-rk3588_defconfig
         make CROSS_COMPILE=aarch64-linux-gnu-
 
+Mask ROM mode
+-------------
+
+Mask ROM mode is the fallback mode of the boot ROM,
+in which it listens for USB commands 0x471/0x472.
+
+Options to get your board into Mask ROM mode:
+
+* Hold the recovery button, depending on firmware support or wiring,
+  while booting the board.
+* Remove any SD cards, removable eMMC or removable UFS modules.
+* Erase any storage media containing boot firmware.
+
+Methods of last resort (USE AT YOUR OWN RISK):
+
+Short the following pins briefly while powering the board, so the boot ROM
+cannot locate any boot firmware and falls back into Mask ROM mode:
+
+* NAND: connect pin 8 and 9 of the NAND flash with a needle.
+* eMMC: connect the clock line to ground.
+
 Flashing
 --------
 
@@ -485,9 +506,9 @@ To write a U-Boot image to the SD card (assumed to be /dev/sda):
 NAND
 """"
 
-Bring device in BootROM mode:
+Bring device in Mask ROM mode:
 
-If bricked and no BootROM mode shows up then connect pin 8 and 9 of the NAND flash
+If bricked and no Mask ROM mode shows up then connect pin 8 and 9 of the NAND flash
 with a needle while reconnecting to the USB OTG port to a PC.
 
 Show connected devices with:
-- 
2.39.5