Nintendo DSi copy protection introduced by Firmware version 1.4 was circumvented by faking a header of a legit game and after the DSi starts booting executing the R4DS multi game loader.
Buy DSi v 1.4 compatible R4 cards
Nintendo has released a new firmware update for the DSi. The firmware update 1.4 adds Facebook image upload application and improves the built in Camera operation speed. However Nintendo update has one GIANT undesirable hidden feature - it tries to blocks DSi compatible flash cartridges from booting on DSi after the firmware update.
Take this as a warning all Nintendo DSi users - DO NOT update until a fix has been found to allow flash cartridge to run on the DSi again. If you don't update the Flash Cards will keep working just fine, but you will not be able to use DSi SHOP. In my opinion a small price to pay for the ability to play all Nintendo DS games for free!
Reported to NOT work after the update are:
(Update: card compatibility has been fixed and by running a .nds update file on DS Lite or a DSi with firmware below 1.4 you can easily update the cards and make them work on firmware 1.4 and 1.4.1)
And most likely all other carts that we have not tested :(
Now lets wait for how long it will take to find a workaround and update the boot loaders and firmware of the DSi flash cards to make them DSI compatible again or to unblock the 1.4 firmware.
R4i team has hacked the DSi 1.4 anti-piracy firmware update. You can expect the update to be released real soon. Here is some wide proof of the 1.4 hack in action.
UPDATE: and in the end the copy protection introduced by DSi Firmware version 1.4 was overcome without creating a custom firmware but by simpley faking a header of a legit game and after the DSi starts booting the code executing the DS Flash Cards multi game loader.
Buy DSi Firmare v 1.4 compatible R4 cards