So, you have increased the size of the flash memory in your device from 4 to 8 MB, right?
You need to investigate from Openwrt sources, where the flash structure for your device is defined and then patch that source file to define 8 instead of 4 MB. And you need to also consider the flash layout structure, so that you do not e.g. overwrite the bootloader, wifi calibration data etc. (in config, art partitions). The layout definitions are platform- & device-specific, so there is no general advice.
EDIT:
My first guess is that you need to use "tplink-8mlzma" instead of "tplink-4mlzma" here:
https://dev.openwrt.org/browser/trunk/t … efile#L496
See also https://wiki.openwrt.org/toh/tp-link/tl … ash_layout
It looks like the config & art are at the end of the 4 MB. You probably need to copy them to the end of the 8 MB, or something similar. You need to check the Tp-link firmware layout definitions in 4 MB vs. 8 MB. Might be this code here:
https://dev.openwrt.org/browser/trunk/t … tplinkfw.c
(Last edited by hnyman on 23 May 2017, 06:46)