The installment, which is part of a total of $4.9 billion that Iran will receive in cash in 10 tranches over the next months, was transferred from South Korea to the CBI's account in Oman.
According to the CBI's policies, these funds can be used by Iran to buy foreign currency, gold or any other item which is not subject to sanctions.  
The $490 million is the first segment in the third phase of unblocking part of Iran's funds held abroad, which the United States says is more than $100 billion.
Iran cannot access its assets overseas due to the sanctions over its nuclear activities, which include restrictive measures imposed on banks and trade restrictions.
The agreement for the transfer of Iran's frozen oil revenues to Oman shows an extension of the Sultanate's efforts to help Iran and the P5+1 group (United States, France, Britain, China, Russia and Germany) reach a final agreement over Tehran's nuclear program, the Times of Oman reported.
Oman, which has friendly ties with Iran, hosted talks between Tehran and world powers, led by the European Union, in November 2014, which paved way for the extension of an interim nuclear deal clinched on November 24, 2013, according to which Iran agreed to curb its nuclear program in return for a limited easing of the sanctions imposed on the country.
This is not the first time that Iran's released funds are being deposited in Oman. In the latest transaction, $500 million was transferred from South Korea to the CBI's account in Oman in the fifth installment of the second phase, while the sixth and last segment worth $400 million were transferred from India to the CBI's account in the United Arab Emirates.
In the first phase, Iran received a total of $4.2 billion, and $2.8 billion of its assets were released during the second phase.   
Earlier, a number of Iranian parliamentarians had stated that the released funds could not be transferred to Iran after being deposited in a second country. Majid Takht Ravanchi, Iran's deputy foreign minister and nuclear negotiator, has said that the CBI does not have any difficulty accessing the unblocked funds.
"These installments are public funds with which we can implement the country's development plans," Takht Ravanchi said.
Meanwhile, Hamid Baeedinejad, another Iranian foreign ministry official, has said that according to the CBI's policies, the funds can be used to buy foreign currency, gold or any other item which is not subject to sanctions.  
The interim accord suspends certain sanctions on gold and precious metals, Iran's auto sector and Iran's petrochemical exports. U.S. persons and entities continue to be prohibited from conducting transactions with Iran, with an exception for the supply of plane spare parts.
The interim deal also allows Iran to continue exporting oil at the current average level of 1 million barrels per day (bpd), rather than forcing continued reductions by buyers.