My experience from my own attempts record during a 24 hr test where that I was able to record any channel by simply pressing the record function while watching my chosen channel but my mag ony recorded 1 minute of the chosen channel.
The mag 254 i was using was not set to any particular timezone infact the date displayed was the default 1/1/2010 date. I then set the timezone using the ntp server settings & found I was no longer able to instantly record (record option was now greyed out) but If I moved forward thruogh the epg, the record function would re - enable after a certain number of hours past in the daily schedule.
This has lead me to a theory, the possible reason for my Mag 254 only recording 1 minute at a time was because the Mag 254 time was set behind the real actual EPG time therefore it would instantly start to record any chosen channel but once the timer tried to progress to the next minute, the mag 254 would realise the time was incorrect & stop the recording. When I used the ntp setting to change my timezone to UK the new UK timezone setting were no longer correct for the recording instantly as the channel I was trying to record was a USA channel in another timezone. Unfortunetely I was unable to investigate this theory any further as my 24 hour trial run out...lol