Formatted /system without backup ROM or SD Card slot I just mistakenly formated /system on my Samsung Galaxy Nexus using the Rom Manager by Clockwork Mod. There was no Image on the system at this point, also there is no SD Card slot on my Galaxy Nexus. 

The Recovery Mode still works and it seems I still could try to install a new ROM. Is there any way to get a new ROM onto my Galaxy Nexus without using SD Cards?
Possible solutions, from the least to the most effort:


Directly adb sideload a working ROM from the PC - provided that your current recovery supports it. Probably not, as CWM is very outdated;
adb push a working ROM from the PC into your phone storage, then flash it using the recovery;
Flash TWRP recovery, then adb sideload a working ROM from the PC;
Flash a factory image via fastboot and start over, as @acejavelin already suggested.


All methods require a PC with working adb and/or fastboot drivers.