Hello,
Router : TP-Link TL-WR841N V14.1
I have upgraded Flash to 16 Mbyte and RAM to 64 Mbyte.
I want to know how to compile snapshots release with 16Mb,64Mb.
Cheers
If you device boots, then you only need to update the device tree. If it doesn't, you'll need to patch the drivers.
In any case, you can't directly modify the kernel source code, so you'll need to follow the steps here.
I can't actually help you any further because I don't own the hardware but that's a good starting point.
You can try existing image first, it should boot, except art would be unavailable. If it does boot, you can modify target/linux/ath79/dts/qca9533_tplink_tl-wr841.dtsi in OpenWrt source tree, to let OpenWrt utilize entire flash space.
Newly installed 16Mb SPI FLASH is empty, I guess I need to load using SPI programmer.
I think you mean for HW V14.1, target/linux/ramips/dts/mt7620a.dtsi
Yes you need a bootloader in the flash chip for it to do anything. The one from the old chip is usually a good place to start. Also copy the factory partition from the old chip, though you could also do that through OpenWrt at run-time. You will need the factory partition data from that particular unit for WiFi to work properly.
The V13 image should boot on this and at least have 8/64. It appears that the V14 is very similar to a V13 except for memory chips.
I don't know about the MT7628, but the old Ralink chips required resistor strapping to change memory size. The pre-boot ROM would read the resistors to set up the RAM controller. This is different from Atheros chips which probe the memory and automatically configure.
Of course, you need a bootloader on the new flash chip at the very least, it could be used to upload a new firmware and other partitions, or you could just write both bootloader and openwrt image in same time, if you put openwrt on correct offset.