Support for a DIR-878 A1 doppelganger: DIR-1935

pastafarian · August 20, 2020, 1:50am

Almost identical to DIR-878 as far as I can tell except it has 8 MiB flash instead of 16 MiB.
The following details are spec'd exactly the same:
* AC1900
* WI1: MT7615N
* WI2: MT7615N
* SWI: MT7621A
* 1x USB 3.0
* AP-MTKH7-0002 REV1.0
Is there any easy way to slim an existing DIR-878 image down to fit in 8 MiB flash? Or is this still more involved?

Thanks for any comments or help!

Lucky1 · August 20, 2020, 8:39am

the size the openwrt is not that big
but the flash memory layout will be different
and needs to be changed to match the new flash chip & size
as you have USB as well it's more like the DIR-882

pastafarian · August 22, 2020, 5:13am

@Lucky1 Thanks for the response and the tip re: DIR-882!

I just got a serial console going on the DIR-1935 and I'm pulling some details and doing a bit of homework. One thing I've found is that it is actually not 8GiB flash, it is 16GiB. I had thought it was 8 GiB based on config flags in the D-Link GPL release, but that seems to be a red herring.

Lucky1 · August 22, 2020, 5:25am

well since you have a serial console capture the factory bootlog
parts if intrest are flash chip type
and flash layout
with this info me can make a DTS
then you can make an inframs image & copy your current flash
these board take both types of flash

tmomas · August 22, 2020, 7:02am

Mega, not Giga.

mpratt14 · August 22, 2020, 11:06pm

In the meantime get familiar with the common DTS between these boards, everything you find should match the information here, paying special attention to the flash partitions at the node called spi0

github.com

openwrt/openwrt/blob/master/target/linux/ramips/dts/mt7621_dlink_dir-8xx-a1.dtsi

// SPDX-License-Identifier: GPL-2.0-or-later OR MIT

#include "mt7621.dtsi"

#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/input/input.h>

/ {
	aliases {
		label-mac-device = &gmac0;
	};

	keys {
		compatible = "gpio-keys";

		reset {
			label = "reset";
			gpios = <&gpio 15 GPIO_ACTIVE_LOW>;
			linux,code = <KEY_RESTART>;
		};

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If everything matches you can make a board specific DTS like the one for DIR-878. All you need is the LED GPIO numbers

github.com

openwrt/openwrt/blob/master/target/linux/ramips/dts/mt7621_dlink_dir-878-a1.dts

// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
/dts-v1/;

#include "mt7621_dlink_dir-8xx-a1.dtsi"

/ {
	compatible = "dlink,dir-878-a1", "mediatek,mt7621-soc";
	model = "D-Link DIR-878 A1";

	aliases {
		led-boot = &led_power_orange;
		led-failsafe = &led_power_green;
		led-running = &led_power_green;
		led-upgrade = &led_net_orange;
	};

	leds {
		compatible = "gpio-leds";

		led_power_orange: power_orange {

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Then you can add a profile similar to the one for DIR-878 which is at line 302 here

github.com

openwrt/openwrt/blob/master/target/linux/ramips/image/mt7621.mk#L302


endef
TARGET_DEVICES += dlink_dir-860l-b1

define Device/dlink_dir-867-a1
  $(Device/dlink_dir-8xx-a1)
  DEVICE_MODEL := DIR-867
  DEVICE_VARIANT := A1
endef
TARGET_DEVICES += dlink_dir-867-a1

define Device/dlink_dir-878-a1
  $(Device/dlink_dir-8xx-a1)
  DEVICE_MODEL := DIR-878
  DEVICE_VARIANT := A1
endef
TARGET_DEVICES += dlink_dir-878-a1

define Device/dlink_dir-882-a1
  $(Device/dlink_dir-8xx-a1)
  DEVICE_MODEL := DIR-882
  DEVICE_VARIANT := A1

For everything else you can look at the commit that added DIR-878

https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=d7233b0a6a9b8cb9207a74a8cb3d0525170cf504

Lucky1 · August 23, 2020, 7:49am

Same PCB same LED's just need to confirm what flash chip NAND or NOR
then to use ether the DIR-882 or DIR-1960
then match flash layout
make sure you use the inframs image to copy the OEM firmware out
you may not be able to easy get an unencrypted copy
and you want to back your factory calibration data at the 1st opportunity

Lucky1 · August 25, 2020, 2:54am

well as a test I flashed the DIR-1935 firmware into my DIR-878
& it's runs fine other then add USB support & a model number change it all works
the boot log shows the same MTD partitions
so it looks the same
if you lazy just use the DIR-882 version
if you could make a DTS with the correct labeling & USB LED count
the difference between 3x3 & 4x4 stream is taken directly from the radio calibration data
so that all sorts it self out

Blackcat1987 · July 18, 2022, 6:46pm

Hello...

After searching the forum for "DIR-1935" looking for DIR-1935 support and reading the few "mentioned search-related" existing posts, I'm having difficulty of accurately interpreting of knowing whether or not the D-Link's model-specific "DIR-1935" is actually supported, or soon to be, or if unsure or etc.

But if-ever the D-Link DIR-1935 is actually supported, would anyone know which firmware I should be choosing?

Please advise.

Thank You.

Borromini · July 18, 2022, 7:33pm

Rule of thumb is that, if you do not find it in the Table of Hardware, then chances of it being supported are close to zero.

What's also important are the specs, and you are not disclosing them. I'm not finding anything on the hardware wikis as to the internals.

Lucky1 · July 18, 2022, 11:15pm

not currently supported but look's like another clone of the dir-886/878/828 or dir-1960/2640/2660
I'm sure this just needs it's flash memory type found out & leds mapped & ID Added to an image
very much the same as this