Hewlett-Packard has added support for an additional 38 printer models or printer series to Snow Leopard, delivering on a promise made shortly after the release of Apple's new operating system when angry users complained that older devices didn't work after upgrading.

On Thursday, Apple posted a printer driver update for Mac OS X 10.6, aka Snow Leopard, but did not call out the specific drivers added to the 51MB driver download.

According to HP, 38 DeskJet, OfficeJet, and LaserJet drivers were added to those made available on Aug. 28, when Apple launched Snow Leopard. Although a list showing only the new drivers has not been published on either Apple's or HP's Web site, the complete list available on the former has been updated to include the new drivers, said Rick Spillers, a member of HP's Mac Connect team.

Among the newly-supported printers are the HP 910 inkjet printer, the DeskJet D1300 series, the OfficeJet 5500 series and the LaserJet M1120.

Almost immediately after Apple started selling Snow Leopard, users who upgraded began griping on the company's support forum that their long-reliable printers were not being recognized by the new OS. Others became angry when an HP representative told them they should buy a new printer if a driver wasn't available for Snow Leopard.

After Thursday's update by Apple, several users reported on the same support forum that they were now able to use their formerly-bricked printers. "Today, I downloaded all the update software for printers and Mac [Snow Leopard], and everything now works fine," said someone identified as "AndyGump" on the same thread where users complained two weeks ago.

"Incredible! HP 1280 working!!!" crowed another user, "omarz," in a message Thursday. "I just update[d] to Snow Leopard 10.6.1 and now suddenly it was detected and it's working!" A driver for HP's PSC 1200 series was one of the 38 included in yesterday's update.

HP's Spillers recommended that users update to Mac OS X 10.6.1 before applying the separate driver update. "Make sure that the printer is turned on and connected via [a] USB cable before launching Apple Software Update," said Spillers in an e-mail reply to questions.

Spillers also said that there has been confusion about how owners of HP all-in-one devices -- which both print and scan, and in some cases also fax, documents -- get their hardware to work with Snow Leopard. "The other interesting thing I've found is trying to educate customers on the new scan interface for HP inkjet All-in-Ones that we've integrated with Snow Leopard," he said.

Apple built support into Snow Leopard for some printer makers' all-in-one devices, adding the functionality to the Image Capture application. HP has posted instructions on how to use its all-in-one printer/scanner hardware with Snow Leopard on its customer support site.

Spillers also took a shot at HP's rivals. "In general," he said, "HP did a great job providing full updated 10.6 drivers for almost all of our products, including LaserJets going back 10+ years. Looking at the [support] forums, it seems that HP is the only print vendor really participating ... not sure I see much input from other print vendors."

Snow Leopard users can manually download the HP driver update from Apple's site, or install it using the Mac's integrated update service.