DigiTimes has reported that Ritek recently received certification for their HD DVD-R and HD DVD-RW media. According to the article, they are the first Taiwanese manufacturer to do so.
Ritek on May 21 announced it has received the certification for both HD DVD-R (recordable, write once) and HD DVD-RW (rewritable) formats, becoming the only Taiwan-based producer of optical discs to receive certification.

The technological barrier for HD DVD-R is quite high and that for HD DVD-RW is higher, Ritek indicated. Ritek's manufacturing capability for DVD+R/-R DL (single-sided double-layer) discs was helpful in obtaining the certification, the company pointed out.
The article also mentions that volume production of the two formats will begin during second half of this year at the earliest. If you'd like to read more, head on over to DigiTimes.