Basically this is what happend. I had an MIUI Rom for ages and decided I want to update it. So I used my SD card and downloaded the new rom and flashed it all worked fine.
I then read I should make a ext partition and in the process of it I broke my sd card some how and my phone stopped booting. So I followed a tutorial to put the Rom back on my phone by using adb push to put the rom in the data partition of my phone. But the data partition on my phone was only 140mb and the miui rom was 180mb so I got a smaller 120mb rom and pushed it to the phone and flashed it using adb shell recovery --update_Package=DATA:Rom.zip or something along those lines.
So the rom was working fine but I really didn't like it so my friend offered for me to use his sd card to put my old rom back. So i went through the process but when I clicked install file from zip it just said "no files found" but I know the rom was there. I tried using the adb shell recovery command except with /sdcard/ rather than DATA and I just got signature verification failed. I disabled signature verification in recovery and it still gave me the same error on the phone but on the command prompt window i keep getting these errors:
insmod: can't insert '/res/modules/crc16.ko': invalid module format
insmod: can't insert '/res/modules/jbd2.ko': invalid module format
insmod: can't insert '/res/modules/ext4.ko': invalid module format
After messing about a bit more my phone crashed so I had to remove the battery and my friends SD card became unreadable and needed formatting. He won't let me use it now lolol.
So now im in a position where my phone won't boot at all and when I try to use adb shell to flash a new rom I get those errors in command prompt and signature verification failed. I've also discovered im getting these errors regardless of whether the rom is there or not.
Sorry for the long post but im desperate and any help would be very much appreciated!