BDP7300/12 does not play LTH Verbatim BluRay

[Millscorner]

Recently bought Verbatim LTH 25 GB BluRay recordables.
On my BDP3000 player it works fine
On my BDP7300/12 player it gives the message: unknown disc.
I am using the latest firmware posted on the support side from philips.
Surfing on internet shows the firmware must be upgraded to play these discs,
strange thing is that my old BluRay player gives no errors.
Anyone suggestions ?

[Oscar]

Unknown disc is normally related to a loader issue ->service.

I would upgrade the device and check if you have not already done this

[Millscorner]

Firmware is the latest available, performed update with USB stick and checked again through a LAN connection for correct firmware.
Firmware is dated 2010, the LTH discs are introduced later, so I guess the firmware on the support site is not up to date.
The strange thing is my older BluRay player, BDP3000 serie does not have a problem with this kind of discs, but this player does not have an optical output for DTS sound.