On https://nitrocaster.me/store/x220-x230-fhd-mod-kit.html is a special mod kit for X220/X230/X230i thinkpads, which replaces the internal LVDS screen with a high resolution eDP screen. For this, several board modifications need to be made (requires soldering skills) and an add-on PCB is installed. It uses the DisplayPort interface from the docking port connector (note: no actual dock required) for adding an eDP screen.
This kit allows you to install a 1080p IPS display in your ThinkPad X220 or X230. You *must* supply the kit+screen yourself if purchasing this mod service, in addition to a suitable screen. You can buy the kit from the above link, and you should buy one of the screens they recommend.
More information about the kit, including how to install it, is on the page linked above.
Why not save yourself the hassle and have RetroFreedom install it for you? I, Leah Rowe, have excellent soldering skills (as shown in my X200 Tablet Libreboot install videos on youtube, aswell as my console modding videos) and can install these quite comfortably, to a high quality standard.
Retroboot includes support for X230 with FHD mod. There is a special coreboot patch which adds a separate board definition for FHD modded X230, such that the FHD kit will play nicer with coreboot. This page has been added to Retroboot; see https://notabug.org/retroboot/retroboot/commit/ea58c5c64765619df3cfff3caa450c0d671b20a3 – Right now, Retroboot releases with pre-compiled ROMs are unavailable for X230_FHD, but if you purchase the Retroboot installation service a ROM will be flashed. Retroboot, based on coreboot, offers many benefits over the Lenovo BIOS, such as faster boot speeds, better security and more customization options. More info on the Retroboot website. Retroboot also supports X220, but there is currently no special patch for FHD mod on X220; the FHD kit will still work just fine with regular coreboot flashed on X220. Retroboot uses coreboot for boot initialization. More info here: https://retroboot.org/
If you buy one of the regular Retroboot X230 laptops from RetroFreedom, and buy this service, your new screen plus FHD kit will be installed for you (you *must* send in the kit+screen. RetroFreedom does not sell FHD kits or eDP screens). Alternatively, you can send in an X230 that you already have, along with screen+kit, and the kit+screen will be installed.
This FHD mod kit installation does *not* include Retroboot flashing. If you want Retroboot (or other coreboot based distro) installed on your X230/X2220, order the flashing installation service here: https://retrofreedom.com/product/libreboot-installation-service/. Alternatively, RetroFreedom can sell you a ThinkPad X230 with Retroboot already installed and install the Full HD kit for you, if you supply the kit and order this installation service.
If sending the kit+screen from outside of the UK, do not declare it as a sale. Declare it as gift/repair, with value of 150 GBP on the customs declaration. That is the average cost of screen+kit when you buy them. Declaring the shipment as “sale of goods” is wrong, because RetroFreedom is not buying the goods from you; rather, you are sending them to RetroFreedom as part of the installation service.