Use any USB flash device with Vista ReadyBoost

Vista says your USB flashdrive is not suitable for ReadyBoost? There's a way around it.

1. Insert your previously unacceptable (for ReadyBoost) USB drive into a USB2.0 port. Vista will auto detect it, load device drivers and show you the auto play window. Ignore it.
2. Open up Computer from your start menu.
3. Right-click the appropriate Removable Media drive and select the Properties menu option.
4. Click the ReadyBoost tab.
5. Uncheck Do not retest this device. Click OK. If you skip this step Windows will retest the device and decide its not usable after all.
6. Remove the rejected device from the computer. We'll plug it back in shortly.
7. Open the Registry Editor (type regedit in the search area of the start menu).
8. If the screen goes dark and you get the user account control prompt, click yes.
9. Find this registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\EMDMgmt
10. Inside the EMDMgmt registry key, all USB keys ever previously connected before are listed with an entry like: _??_USBSTOR#Disk&Ven_SanDisk&Prod_Cruzer_Micro&Rev_0.1#20042203920759B05025&0#{53f56307-b6bf-11d0-94f2-00a0c91efb8b}_2253922835
11. Inside that long cryptic key there are some values you can control. You're interested in two of them that affect ReadyBoost.So locate a registry subkey that belongs to your USB flash disk. If you don't recognize the cryptic code for your USB flash disk (hint: it frequently contains the brand name), If you fail to recognize the name of your USB flash device brand or model, look for one where DeviceStatus = 4 (It failed the ReadyBoost check).
12. Double click DeviceStatus and change it to 2. (It just passed the ReadyBoost check ;) )
13. Double click WriteSpeedKBs and it to 1000 (Decimal) or 3e8 (Hex). You could go higher but the results may be bad. Just don't set WriteSpeedKBs to 1000 (Hex) accidentally.
14. Put that USB flash back into the computer. Skip the auto play stuff.
15. Open Computer on your start menu just like before.
16. Right-click the Removable Disk drive corresponding to the USB flash device. Select Properties on the menu.
17. Click the ReadyBoost tab.
18. Select the Use this device button.
19. Click OK. You are now getting some benefit from ReadyBoost from your slower flash drive. You've gotten windows to behave in a way it wasn't designed to, albeit in an expected manner. Don't worry, it won't let you down with unexpected stuff - but if you're using your hacked ReadyBoost device the unpredictability will happen a little faster.