There is no need to 'hack' or 'jailbreak' a Kobo reader—they can read PDFs natively. The following comes from their site:
You'll find some differences when you're reading PDF books compared to
regular books, including the option to read in landscape orientation,
and to zoom in on the page.
Here are some things you can't do with a PDF book: Select text Add
highlights Look up words in the dictionary Change the text size or
style
This applies to Kobo Mini, Kobo Original / Kobo Wifi, Kobo Touch, Kobo Glo, Kobo Aura HD, Kobo Aura, and Kobo Aura H20.
Also on their site, there are instructions for how to load a PDF onto a Kobo Original:
The Kobo Wireless and Kobo Original eReaders support documents in PDF
format.
You can transfer them to your eReader:
By drag-and-drop On an SD card If your PDFs are protected by Adobe
DRM, you must use Adobe Digital Editions to transfer them to your
eReader.
For use with the SD card:
If your PDFs are not protected by Adobe DRM, you can transfer them to
your eReader using a SD card.
Insert the SD card with the PDF files on it into your eReader's SD
card slot. Turn on your eReader. Wait for your eReader to process the
content. Find the documents under Documents.
while for drag and drop:
Connect your eReader to your computer using the USB cable.
On your eReader select Manage Library.
Press the centre of the Navigation pad.
Open Finder (on a Macintosh computer) or Explorer (on a Windows
computer), and look for KOBOeReader. This may be listed as a hard
drive or as a removable storage device.
In another Finder or Explorer window, locate the files you want
to transfer. Drag these files to KOBOeReader. You can now eject
your eReader and read your documents.
Since PDF is now a standard, most e-readers support it, so Kobo is not unique in this regard—Kindle and Nook both read PDFs as well. Also, you might check out the sidelighing of the Kobo Glo—it's not at all bright or glaring, but offers comfortable reading in any light level. Looks really nice—my mom loves hers.