起，從走巳聲，orly?

[Hofmann]

說文解字 says 起 is 從走巳聲, i.e. 走 is the semantic component and 巳 is the phonetic component. I have a hard time believing it because 起 doesn't sound much like 巳 in Old Chinese or Middle Chinese. What kind of character is this actually? And if you want to suggest that the phonetic component is actually 己, please prepare to account for that almost every instance of 起 before Shinjitai had 巳 on the right.

[chevil]

Interesting question. Well, Karlgren apparently places it in the same GSR series as 己、記、紀、etc. (GSR 953), so it's possible that 己 is the phonetic, although it's also possible Karlgren made a mistake. Also, consider that Baxter and Sagart (possibly for this very reason) reconstruct 巳 with a uvular initial *s-ɢəʔ (which often has contacts with velars), while they reconstruct *C.qʰəʔ for 起.

Also, note the reconstructions of 己 and 已 in their system, *kəʔ and *ɢəʔ, respectively. Just some food for thought.