@lengolad
If you didn't check the HWID before you started you may have used the wrong firmware to make the Cure3 fw and inadvertently flashed the wrong one. 13/14xx devices have two possible HWIDs because of different chips, HWID 0972 and HWID 1106.

Probably the message you received was in full "System Software Missing" which usually indicates wrong fw_all.bin flashed to region 14. It might have been possible to revive it while still powered on, but that chance is usually lost once it's been completely shut down it after flashing an incompatible fw. To explain: A wrong boot.bin flash can result in no subsequent re-boot because of foreign bootloader and x-loader now present in regions 5 and 43, via virtual region 12, now being incapable of booting the device. If that's happened it's likely dead and cannot be revived by any software method, only by replacing the main flash chip which isn't economically feasible anyway.

Try these tips if you're sure you flashed the correct fw version to match it's HWID:
(i) Take it into a completely dark room and see if there's a feint backlight on the screen in case it's not even booting to the logo splash screen, if not;
(ii) Open it and disconnect the battery for a time, at least 5 minutes and preferably longer, even overnight. That drains all electrical components. After you reconnect battery and try to power it on if still no start screen or any screen backlight it's likely now only useful to harvest parts like the screen and battery etc..