Do you still see a generic icon or no icon at all?

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.com/kb/Safe+Mode

Make sure that the pref browser.chrome.favicons is true on the about:config page.

To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website.
If you see a warning then you can confirm that you want to access that page.

• Use the Filter bar at to top of the about:config page to locate a preference more easily.
• Preferences that have been modified show as bold (user set).
• Preferences can be reset to the default via the right-click context menu if they are user set
• Preferences can be changed via the right-click context menu: Modify (String or Integer) or Toggle (Boolean)

See also:

• CheckPlaces: https://addons.mozilla.org/firefox/addon/checkplaces/

Still just generic icons on my bookmarks. Can't seem to resolve the issue.

Make sure that you do not run Firefox in permanent Private Browsing mode.

• https://support.mozilla.com/kb/Private+Browsing

You enter Private Browsing mode if you select: Tools > Options > Privacy > History: Firefox will: "Never Remember History"

To see all History and Cookie settings, choose: Tools > Options > Privacy, choose the setting Firefox will: Use custom settings for history

• Deselect: [ ] "Automatically start Firefox in a private browsing session"

Yup. Set as above, but no icons still.