Samata Ullah pleaded guilty to being a member of the Islamic State, terrorist training, preparing terrorist acts and possessing articles for terrorist purposes.
He denied one charge of directing terrorism.
The Old Bailey court in London heard the Attorney General had decided to accept the pleas.
The remaining charge will lie on his file, the BBC reported.
When he was arrested on September 22, he had a USB cufflink with an operating system loaded onto it to conceal a hoard of extremist data, including a blog.
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He also admitted having a book entitled Guided Missiles Fundamentals AFM 52-31 and an electronic version of Advances in Missile Guidance, Control and Estimation for terrorist purposes.
Prosecutor Brian Altman said a hi-tech report dealt with Ullah's desire to copy his blog onto a platform in a "format that meant it could not be closed down or deleted by the authorities".
Ullah, who has been diagnosed with autism, admitted the charges earlier in March but his pleas could not be reported until after the the prosecution had time to consider whether to go ahead with a trial on the remaining charge.
He said the "issue of dangerousness" would have to be looked at before sentencing.