He passed his miqaat and did not enter ihram from there, then he entered ihram from the miqaat of Madinah

Firstly:

There is some scholarly discussion about the miqaat of the people of Sudan; this has been mentioned in the answer to question no. 41978. 

Secondly: 

If the people of Sudan come to Jeddah and their miqaat was al-Juhfah, or in line with Yalamlam, or Jeddah itself – according to the details discussed in the question referred to above –  but they do not enter ihram from their miqaat, then they go to Madinah and they enter ihram from Abyar ‘Ali, their ihram is valid. That is because it is permissible for the one who passes by two miqaats to delay entering ihram until he reaches the second miqaat, according to the more correct scholarly opinion; this is also the view of the Hanafis. 

It says in Kanz ad-Daqaa’iq: If a person from Madinah does not enter ihram from Dhu’l-Hulayfah [Abyar ‘Ali], and he enters ihram from al-Juhfah, there is nothing wrong with that. The same applies to anyone who passes by it who is not one of its people. 

It was narrated from Abu Haneefah that (the one who does this) must offer a compensatory sacrifice, and that applies the closer the second miqaat is to Makkah. 

However, the first view is more correct. When ‘Aa’ishah (may Allah be pleased with her) wanted to do Hajj, she entered ihram from Dhu’l-Hulayfah, and when she wanted to do ‘umrah she entered ihram from al-Juhfah. It is as if she wanted to increase the reward in Hajj because it is of greater virtue. If al-Juhfah had not been a miqaat for her, it would not have been permissible for her to delay entering ihram for ‘umrah, because there is no difference between Hajj and ‘umrah with regard to the miqaat for those who are coming from beyond the miqaat boundaries.

End quote from Tabyeen al-Haqaa’iq Sharh Kanz ad-Daqaa’iq (2/7) 

The scholars of the Standing Committee (11/155) were asked:

A pilgrim intends to do Hajj but he had business to attend to in Makkah, then in Madinah. He passed the miqaat without entering ihram, and entered Makkah, then he went to Madinah, and entered ihram from the miqaat of Madinah for Hajj. What is the ruling on his actions? 

They replied: 

So long as the pilgrim went out to the miqaat of the people of Madinah and entered ihram, there is nothing wrong with him having entered Makkah without entering ihram, although it would have been better for him to enter ihram from the first miqaat. End quote. 

Standing Committee for Academic Research and Issuing Fatwas 

‘Abdullah ibn Ghadyaan, ‘Abd ar-Razzaaq ‘Afeefi, ‘Abd al-‘Azeez ibn ‘Abdullah ibn Baaz 

Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) was asked: A man came from Jeddah and did not enter ihram; first of all he went to al-Madinah al-Munawwarah to visit the Prophet’s Mosque, then he entered ihram from the miqaat of the people of Madinah. Is that valid?

He replied: There is nothing wrong with it. If a person comes from his country heading to Madinah first, and he stops in Jeddah then goes from Jeddah to Madinah, then he comes back from Madinah, entering ihram at the miqaat of the people of Madinah, there is nothing wrong with that.

End quote from Liqa’ al-Baab al-Maftooh, no. 121 

And Allah knows best.