A senior Nigerian officer jailed for allowing weapons to fall into the hands of Boko Haram Islamists has had his sentence quashed, according to an Army Council circular seen by AFP Friday.

Brigadier General Enitan Ransome-Kuti, a nephew of the Afrobeat legend Fela Kuti, was convicted at a court martial in October last year of failure to discharge his duties and "loss of equipment".

He was cleared of a separate charge of "cowardly behaviour" in relation to the attack on the town of Baga, on the shores of Lake Chad, in northeastern Nigeria, in January 2015.

The Army Council circular, dated March 1, said the panel had reviewed Ransome-Kuti's case and upheld the failure to discharge duties conviction but demoted him in rank to colonel.

"The council also quashed the finding of guilty and award of six months imprisonment... on count three ('miscellaneous offences relating to service property') and replaced (the) same with a finding of 'not guilty'," it added.

Ransome-Kuti's case was among the most high-profile in a string of accusations against Nigerian soldiers in the fight against Boko Haram.

The Baga attack -- believed to be the worst since the insurgency began in 2009 -- saw hundreds of militants overrun and destroy the town and surrounding villages, including a military base.

Fighters were later seen in a propaganda video picking through weapons including sub-machine guns, mortars and grenades at the base, which was used by troops from Nigeria, Niger and Chad.

In September 2014, 12 soldiers were sentenced to death for mutiny after shots were fired at their commanding officer in the northeastern city of Maiduguri.

The following December, 54 others were sentenced to death for refusing to deploy for an operation. Troops had long complained of a lack of adequate weapons and even bullets.

The military announced in May last year that 579 officers and soldiers were on trial over alleged indiscipline linked to the conflict. But there have been calls for reviews of the cases.