He was arrested again in February 1976 at a Garda roadblock in Ballinrobe, County Mayo after attending the funeral of Frank Stagg. On 16 February, he was charged with IRA membership at the Special Criminal Court in Dublin, and sentenced to 18 months in prison. In March 1977, Ferris took part in a hunger strike along with 20 other prisoners, demanding a public inquiry into conditions in the prison. After 32 days he was transferred to Curragh Military Hospital. The hunger strike ended after 47 days. A guarantee had been given to the prisoners by Bishop James Kavanagh that the government would work to improve prison conditions. Although conditions improved somewhat, Tim Pat Coogan—a nationalist historian and former editor of "The Irish Press"—noted that after a visit in 1977 tensions still remained, and mentioned reports of visitors being denied visits after long distances and that strip searching was still carried out. Ferris was released two months later in June 1977.