Ryan, 78, is serving 6 1/2 years for racketeering, conspiracy, tax fraud and lying to the FBI.
The Supreme Court, in a short order, told the lower court to hear Ryan's appeal "in light of Wood vs. Milyard."
In that ruling last week, the high court said a court cannot deny constitutional review based on issues prosecutors did not raise -- for example, if a defendant had waited too long to appeal.
Ryan's second appeal to the U.S. Court of Appeals for the Seventh Circuit in Chicago said jury instructions and evidentiary rulings were not allowed under Supreme Court precedent, the Courthouse News Service reported.
Those errors allowed the jury to convict him on a denial of honest-services theory without separately finding a bribe or kickback, Ryan's lawyers argued.
But the appeals court disagreed, Courthouse News reported. "Jury instructions that misstate the elements of an offense are not themselves a ground of collateral relief; likewise with erroneous evidentiary rulings," Chief Judge Frank Easterbrook said.
Ryan was convicted in 2006 of awarding state contracts to friends and donors while he was secretary of state and governor in exchange for money and gifts, Courthouse News said.