Like Japanese Budo, I'm sure Korean Mudo has a definition.
Mudo
무도 is the Korean rendering of budo;
武道.
Was is the Korean Mudo code? I'm sure it has to differ in language, if not idea, from the Budo code. Please post it if you have it.
I've never seen an historical "mudo" code, and until the nineteenth century, I'm not even sure that the word existed in Korean martial systems. In the same way that until the twentieth century, geomdo probably did not exist as a term in Korean sword systems (there is no evidence of it).
There is no mention of the term "mudo" in the Muyedobotongi. Muye (
武芸) means martial arts. The Muyedobotongi makes no mention of martial codes. In fact, many of the modern terms KMA-ists like to think of as traditional are missing. Which is hardly surprising; language evolves and the Muyedobotongji was the final revision of a work that was copied a couple of centuries earlier (or more), and it was published in the eighteenth century.
The closest thing that I can think of to a "mudo code" would be the Hwarang code.
AncientKorean code of conduct associated with the Hwarang
Sagun Ee Chung 사군이충/ 事君以忠 – Loyalty to one's king.
Sa Chin Ee Hyo 사친이효 / 事親以孝 – Respect to one's parents.
Kyo U Ee Sin 교우이신 / 交友以信 – Faithfulness to one's friends.
Im Seon Mu Tio 임전무퇴 / 臨戰無退 – Courage in battle.
Sal Saeng Yu Taek 살생유택 / 殺生有擇– Justice in killing.
I am not certain if this is historical, but there is nothing so radical here that I would call it into question; the fact that so little is really known about the Hwarang, and so much is simply made up, that almost anything I read about the Hwarang I take with a grain of salt.
Some where I saw this:
Ye jôl 예절: ThreeEtiquettes;
a.)사친이국기Respectfor the Flag
b.)사친이사범님과선배 Respectfor Masters and Seniors
c.)사친이동료Respect for Colleagues
I don't remember where, but I liked it. Historical "mudo?" Probably not.
Finally, we have General Choi's tenets (copied from Wikipedia):
Taekwon-Do Tenets
There are five tenets defined in the ITF.
Courtesy (Ye-ui / 예의
Showing courtesy to all, respecting others, having manners as well as maintaining the appropriate etiquette at all times, both within and outside the dojang (도장

(designated training area).
Integrity (Yeom-chi / 염치
Although it may be similar, this form of integrity takes on a more wider role then defined in the common dictionary. In Taekwondo, integrity means not only to determine what is right or wrong but also having the conscience to feel guilt if one has done wrong and to have the integrity stand up for what is right.
Perseverance (In-nae / 인내
One will persevere time and time again until they have achieved a result which is adequate towards what one was trying to achieve.
Self-control (Geuk-gi / 극기
This means to not only have control over one's physical acts, but also their mental thoughts and actions.
Indomitable spirit (Baek-jeol-bul-gul / 백절불굴
To have indomitable spirit means to have the courage to stand up for what you believe in,no matter what odds you are up against, and to always give 100% effort in whatever you do.
I have seen General Choi's tenets repeated in the text of more than one postwar Korean martial art outside of TKD.
None of what I have posted is unique to the martial arts, and all comes from Confucian values, which were important to Korean culture.
I hope that helps.