There is a issue in source. I commented it and will be fixed soon. But it won't cause any issue in usage. You'll update to fixed version later. You should select Redmi R2100. Just for now. You'll select Mi R2100 after todays build. It'll be fixed.
I said white because you mentioned RM2100.
RM2100 = white
R2100 = black
Ignore it. Click RED Warning button below. Image isn't uncompatible. Just openwrt thinks like that because you was at RM2100 before and you are tryya switch R2100 now.
A much better way than using .config files (which are extremely code and version dependent):
Use the config.buildinfo = also called config seed, copy the content into a blank, newly created .config and place it into your openwrt dir. Then use make defconfig. It will blow the few lines up to a whole config file which fits to your codebase and your version.
You could just use the config.buildinfo from @emirefek . I would never suggest to use full config files as they are not portable in most cases.
Another advantage: You can rewrite it extremely easy for another device.
Just have a look at this example
My config seed for the basic image version I'm currently providing for RM2100 (white edition):
CONFIG_TARGET_ramips=y
CONFIG_TARGET_ramips_mt7621=y
CONFIG_TARGET_ramips_mt7621_DEVICE_xiaomi_redmi-router-ac2100=y
CONFIG_ALL_KMODS=y
CONFIG_DEVEL=y
CONFIG_KERNEL_BUILD_DOMAIN="buildhost"
CONFIG_KERNEL_BUILD_USER="builder"
# CONFIG_KERNEL_KALLSYMS is not set
CONFIG_OPENSSL_ENGINE=y
CONFIG_OPENSSL_PREFER_CHACHA_OVER_GCM=y
CONFIG_OPENSSL_WITH_ASM=y
CONFIG_OPENSSL_WITH_CHACHA_POLY1305=y
CONFIG_OPENSSL_WITH_CMS=y
CONFIG_OPENSSL_WITH_DEPRECATED=y
CONFIG_OPENSSL_WITH_ERROR_MESSAGES=y
CONFIG_OPENSSL_WITH_PSK=y
CONFIG_OPENSSL_WITH_SRP=y
CONFIG_OPENSSL_WITH_TLS13=y
CONFIG_PACKAGE_ca-bundle=y
CONFIG_PACKAGE_cgi-io=y
CONFIG_PACKAGE_hostapd=y
# CONFIG_PACKAGE_iw is not set
CONFIG_PACKAGE_iw-full=y
CONFIG_PACKAGE_libiwinfo-lua=y
CONFIG_PACKAGE_liblua=y
CONFIG_PACKAGE_liblucihttp=y
CONFIG_PACKAGE_liblucihttp-lua=y
CONFIG_PACKAGE_libopenssl=y
CONFIG_PACKAGE_libopenssl-conf=y
CONFIG_PACKAGE_libubus-lua=y
CONFIG_PACKAGE_libustream-openssl=y
CONFIG_PACKAGE_lua=y
CONFIG_PACKAGE_luci=y
CONFIG_PACKAGE_luci-app-firewall=y
CONFIG_PACKAGE_luci-app-opkg=y
CONFIG_PACKAGE_luci-base=y
CONFIG_PACKAGE_luci-lib-ip=y
CONFIG_PACKAGE_luci-lib-jsonc=y
CONFIG_PACKAGE_luci-lib-nixio=y
CONFIG_PACKAGE_luci-mod-admin-full=y
CONFIG_PACKAGE_luci-mod-network=y
CONFIG_PACKAGE_luci-mod-status=y
CONFIG_PACKAGE_luci-mod-system=y
CONFIG_PACKAGE_luci-proto-ipv6=y
CONFIG_PACKAGE_luci-proto-ppp=y
CONFIG_PACKAGE_luci-ssl-openssl=y
CONFIG_PACKAGE_luci-theme-bootstrap=y
CONFIG_PACKAGE_openssl-util=y
CONFIG_PACKAGE_rpcd=y
CONFIG_PACKAGE_rpcd-mod-file=y
CONFIG_PACKAGE_rpcd-mod-iwinfo=y
CONFIG_PACKAGE_rpcd-mod-luci=y
CONFIG_PACKAGE_rpcd-mod-rrdns=y
CONFIG_PACKAGE_uhttpd=y
CONFIG_PACKAGE_wpa-supplicant-mesh-openssl=y
# CONFIG_PACKAGE_wpad-basic is not set
If you want to use exactly the same options and packages for R2100 you would have to replace only a single line:
Replace the third line by:
So you see these smaller seed files have a lot of advantages and aditionally a much better readability as you can directly see what is different in comparison to the default packages.
Btw.: I will update all my 19.07.x branches during this afternoon to use exactly the same names as on openwrt/master to bring it in line.
Alright, I am now on your image and will try my own attempts once this gets fixed.
I didn't see a button to force the sysupgrade (using bootstrap theme). For everyone with the same issue just use the sysupgrade --force flag via ssh and it will be fine.
Thanks for the suggestion. Is there any tool that helps me generating my own config.buildinfo or is there a config seed available for every supported device?
Awesome, looking forward to experiment more with it. Are there any drawbacks when compiling the Kernel with MIPS FPU Emulator?
You cannot generate your own config.buildinfo it is just output when you compile firmware. This a file for announce which modules you integrated in menuconfig. The only way to generate config is using menuconfig. I'm not sure but I don't think @scp07 meaned you to use my config.buildinfo It should be like catch what option you should choose at menuconfig.
Glad to it worked. If you got any issue or bug report both me and scp07
I think you should fix issue at your RPi first. Could you please rm -Rf /path/cloned/git/repo and start all over guide again. And please check. Are you sure you got all dependencies. I think you are not. I'm saying this again but RPi is so weak for this job. I tried with Snapdragon855 before and I just cancelled it after much time. You can got vps at Hetzner or Vultr(which I'm doing same thing) They costing hourly.
Edit: Thanks both @ilyas and @scp07 you helped soo much on my PR. You are answering all my questions for a week. Thanks a lot. It's just your PR more than me
Why do you think so? I already corrected everything together with emirefek and he already verified it on his device. It should be correct in my repository and also in the PR.
How to generate a proper config for compiling your own images:
At first read Quick Image Building Guide
Dependencies mentiond in the official repository: gcc, binutils, bzip2, flex, python3.5+, perl, make, find, grep, diff, unzip, gawk, getopt, subversion, libz-dev, libc headers.
clone your favorite repository with git clone <URL> e.g. git clone https://github.com/phs07/openwrt.git
checkout to the branch you want to use for the compilation e.g. git checkout openwrt-19.07.3_xiaomi_router_ac2100
Now follow this procedure:
Run ./scripts/feeds update -a and then ./scripts/feeds install -a
Optional: If you want to use a provided config template copy everything form the config.buildinfo into a new .config file in your openwrt sourcecode folder
Run make defconfig
3.1 Optional: If you want to make some changes or include other packages (e.g. luci-ssl for a Web UI) run make menuconfig and apply your changes
3.2 Optional: If you already compiled something and want to start with a clean compile just use make clean
Run make download
Run make -j<cpu_cores> e.g make -j4
The config.buildinfo is automatically generated after every compilation and is located in the device's target bin folder.
Advantage over using .config files directly: Much cleaner build process and it will also work after version changes e.g. from 19.07 to master (this wouldn't work with full config files).
I need someone who has knowledge about SPI/UART
In Xiaomi Mi Router AC2100 (black, cylinder)
I don't have any knowledge about SPI/UART. I need someone to help me to build wiki page for serial section.
As there was a lot of confusion about namings, configurations etc. I hereby want to give you an updated overview over the latest stable version.
All repositories are updated and can be used for both: the black cylinder and the white 6-antenna version. In make menuconfig both are namend clearly so that you can easily select them.
@emirefek: What else do you need? It seems that you already have all the information. The connection is labeled perfectly on the board and the settings should be the same as for RM2100.
Any chance you guys could simplify the explanation of the process for people who do not have programming experience? I bet there's plenty of us lurking here trying to follow. Thank you very much for the support btw!
ok if you're planning on doing a PR to openwrt, be aware that the LEDs for the "black" aren't really correct yet 
