FS#3960 - Xiaomi MiWifi Nano 3C/ R3C/ R3L dts mismatch causes the device not to boot

[openwrt-bot]

vamanea:

Supply the following if possible:

• Device problem occurs on
  Xiaomi MiWifi R3L
• Software versions of OpenWrt/LEDE release, packages, etc.
  OpenWrt v19.07.7
• Steps to reproduce

1. From the Wiki at https://openwrt.org/toh/xiaomi/mir3c flash the sysupgrade image: http://downloads.openwrt.org/releases/19.07.7/targets/ramips/mt76x8/openwrt-19.07.7-ramips-mt76x8-miwifi-nano-squashfs-sysupgrade.bin
2. Device does not boot anymore

The problem is the dts MIWIFI-NANO.dts defines a incompatible layout of the flash, which ends up flashing OpenWrt to the wrong part of the flash.
The OEM partition layout is:

[ 1.510000] 0x000000000000-0x000001000000 : "ALL"
[ 1.510000] 0x000000000000-0x000000030000 : "Bootloader"
[ 1.520000] 0x000000030000-0x000000040000 : "Config"
[ 1.530000] 0x000000040000-0x000000050000 : "Bdata"
[ 1.530000] 0x000000050000-0x000000060000 : "Factory"
[ 1.540000] 0x000000060000-0x000000070000 : "crash"
[ 1.550000] 0x000000070000-0x000000080000 : "cfg_bak"
[ 1.550000] 0x000000080000-0x000000140000 : "overlay"
[ 1.560000] 0x000000140000-0x0000008a0000 : "OS1"
[ 1.610000] 0x0000002a0000-0x0000008a0000 : "rootfs"
[ 1.610000] 0x0000008a0000-0x000001000000 : "OS2"


with emphasis on OS1 and OS2.

However MIWIFI-NANO.dts defines firmware partition as:

partition@50000 {
compatible = "denx,uimage";
label = "firmware";
reg = <0x50000 0xfb0000>;

                    };

The bootloader will boot either OS1 or OS2 -> we get an unbootable device.

Now we have two similar devices, MiWifi Nano R1 and R3L/R3C with different partition layout but the wiki proposes to flash the same image: https://openwrt.org/toh/xiaomi/mir3c https://openwrt.org/toh/xiaomi/miwifi_nano I personally still use my R3L so I would propose we add a new device type that could cover R3L.