The Optimus Maximus keyboard developed by Russian designer Artemy Lebedev has been delayed once again, this time by problems with the device's firmware.

Art Lebedev Studio had expected the first Optimus Maximus keyboards to ship in late December, but the release date has been pushed back to late February. He blamed the delay on a chip that powers the customisable keyboard.

"We have chosen a Philips processor that fully satisfied all our requirements. But as it is new as a product for Philips, they still experience some problems with the processor and we are compelled to work with draft documentation," Lebedev wrote this week in a blog post.

Customers who have already paid and can't wait to get their hands on the keyboard, which has a tiny, customisable OLED (organic light-emitting diode) screen on each key, can opt to receive a keyboard before the firmware issue is resolved. These keyboards already have "basic functionality", such as the ability to switch images displayed on the keys, but Lebedev said upgrading the firmware later on could be difficult for many users.

"If you do not have professional skills you may run into troubles installing and updating software," he wrote.

The OLED screens used in the Optimus Maximus' 113 keys can be customised by users, allowing the keys to change depending on what language a user is typing in, or which application is being used. Users can also change the font and colour of the letters displayed on each key.

Lebedev began taking orders for the Optimus Maximus in May, with each keyboard priced at $1,564. (£800).

In November, Lebedev announced plans to offer several additional versions of the Optimus Maximus that have fewer keys equipped with OLED screens and therefore cost less.

The cheapest of these versions, priced at $427, has just one customisable key: the space bar. A version with 10 customisable keys costs $599 and one with 47 customisable keys is priced at $999.

Lebedev plans to show off the Optimus Maximus keyboard at the CES show in Las Vegas next month.