Upgraded my i5 ThinkPad X220 with an i7 motherboard bought on eBay. Think I figured out why ethernet is the only thing that doesn't work : r/techsupportgore
Lenovo Thinkapad X220 Motherboard with CPU Intel Core i7-3520M 04W6720 *WORKS* - Laptop-Masters
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Motherboard W/ i5-2520M for Lenovo ThinkPad X220 04W0677
04y1834 Motherboard Fru Thinkpad X220 Notebook I7-2640m - Buy Motherboard For Thinkpad X220,04y1834 Product on Alibaba.com
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LENOVO X220 motherboard Nairobi, Kenya.
winux: Upgrading Lenovo X220 with X230 motherboard - Part 1