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

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!

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

@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.

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

Mega, not Giga.

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

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

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

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

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

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