[Galaxy S III I9305 (4G LTE + 2GB RAM) Q&A, Help & ] MeteorKing:
EDIT: Must have screwed something up earlier in the process, I did get a couple of errors at that point but figured I'd solved them by re-flashing recovery via odin, which did make the errors in recovery go away - guess that was only a symptom, not the cause. Turns out even the backup only booted once before getting stuck the same way, and ran very slowly when it did work.

I fixed it by restoring a completely stock ROM via Kies as per this thread: http://xdaforums.com/showthread.php?t=1984717 then reflashing recovery and installing the Cyanide-L as per the instructions. All seems fine now.

I've spent all day trying to get various custom ROMs working on my Galaxy S3 4G (I9305T). Followed instructions closely, tried multiple Lollipop and a KitKat ROM, nothing. Currently using TWRP 2.8.7.3, have used others as instructed by the ROMs, though for SlimLP I used both that and a newer version of the one recommended there (as the linked one didn’t seem to work) in various attempts.

ROMs I've tried:

SlimLP 5.1.1, both the latest and previous version.

Cyanide 5.1.1

Resurrection Remix LP 5.5.9

L-Droid v4.0

Cleared everything before install (factory reset and individual wipes of system, cache, dalvik cache and data), used ext4 or f2fs where appropriate, various recoveries as mentioned, absolutely nothing happening.

Using

C:\Program Files (x86)\Android\android-sdk\platform-tools>adb logcat -v long > pleasework.txt

I get:

--------- beginning of /dev/log/main

[ 01-13 17:31:38.805 1946: 1946 I/installd ]
installd firing up
[ 01-13 17:31:38.805 1946: 1946 E/cutils ]
Failed to read /data/.layout_version: No such file or directory
[ 01-13 17:31:38.805 1940: 1940 I/DEBUG ]
debuggerd: Dec 6 2014 18:41:24
[ 01-13 17:31:38.805 1946: 1946 E/installd ]
Could not create directories; exiting.
[ 01-13 17:31:38.815 1938: 1938 I/kickstart-qcks ]
PARAMETER VALUES
[ 01-13 17:31:38.815 1938: 1938 I/kickstart-qcks ]
COMPORT_DLOAD=/dev/ttyUSB0
[ 01-13 17:31:38.815 1938: 1938 I/kickstart-qcks ]
COMPORT_SAHARA=/dev/ttyUSB0
[ 01-13 17:31:38.815 1938: 1938 I/kickstart-qcks ]
PATHTOIMAGES=/firmware/image/
[ 01-13 17:31:38.815 1938: 1938 I/kickstart-qcks ]
PATHFORRAMDUMP=/data/cp_log/
[ 01-13 17:31:38.815 1938: 1938 I/kickstart-qcks ]
EFSRAW1=/dev/block/modem/m9kefs1
[ 01-13 17:31:38.815 1938: 1938 I/kickstart-qcks ]
EFSRAW2=/dev/block/modem/m9kefs2
[ 01-13 17:31:38.815 1938: 1938 I/kickstart-qcks ]
EFSRAW3=/dev/block/modem/m9kefs3
[ 01-13 17:31:38.815 1938: 1938 I/kickstart-qcks ]
Header1=efs1.mbn
[ 01-13 17:31:38.815 1938: 1938 I/kickstart-qcks ]
Header2=efs2.mbn
[ 01-13 17:31:38.815 1938: 1938 I/kickstart-qcks ]
Header3=efs3.mbn
[ 01-13 17:31:38.820 1938: 1938 I/kickstart-qcks ]
Testing if port "/dev/mdm" exists
[ 01-13 17:31:38.820 1938: 1938 I/kickstart-qcks ]
Trying to bring MDM9K out of reset
[ 01-13 17:31:38.820 1938: 1938 I/kickstart-qcks ]
Testing if port "/dev/ttyUSB0" exists
[ 01-13 17:31:38.820 1938: 1938 E/kickstart-qcks ]
MDM9x15 Boot protocol is SAHARA
[ 01-13 17:31:38.820 1938: 1938 I/kickstart-qcks ]
EFS Prepend
[ 01-13 17:31:38.820 1938: 1938 E/kickstart-qcks ]
File '/firmware/image/efs1.mbn' was not found
[ 01-13 17:31:38.820 1938: 1938 E/kickstart-qcks ]
Prepend failed.
[ 01-13 17:31:38.820 1949: 1949 E/SMD ]
SMD Main entered
[ 01-13 17:31:38.825 1948: 1948 D/macloader ]
Deleting file /data/.cid.info
[ 01-13 17:31:38.950 1942: 1942 I/SurfaceFlinger ]
SurfaceFlinger is starting
[ 01-13 17:31:38.950 1942: 1942 I/SurfaceFlinger ]
SurfaceFlinger's main thread ready to run. Initializing graphics H/W...
[ 01-13 17:31:38.970 1942: 1942 D/libEGL ]
loaded /system/lib/egl/libEGL_mali.so
--------- beginning of /dev/log/system
[ 01-13 17:31:38.995 1937: 1937 I/Vold ]
Vold 2.1 (the revenge) firing up
[ 01-13 17:31:38.995 1937: 1937 D/Vold ]
Volume sdcard1 state changing -1 (Initializing) -> 0 (No-Media)
[ 01-13 17:31:38.995 1937: 1937 D/Vold ]
Volume usbdisk0 state changing -1 (Initializing) -> 0 (No-Media)
[ 01-13 17:31:39.010 1985: 1985 I/ldroid ]
Welcome to Android 4.4.4 / L-Droid v4.0.kk-final
[ 01-13 17:31:39.015 1939: 1939 I/Netd ]
Netd 1.0 starting
[ 01-13 17:31:39.040 1942: 1942 D/libEGL ]
loaded /system/lib/egl/libGLESv1_CM_mali.so
[ 01-13 17:31:39.045 1947: 1947 E/keystore ]
chdir: /data/misc/keystore: No such file or directory
[ 01-13 17:31:39.045 1950: 1950 E/Diag_Lib ]
Diag_LSM_Init: Failed to open handle to diag driver, error = 13
[ 01-13 17:31:39.050 1942: 1942 D/libEGL ]
loaded /system/lib/egl/libGLESv2_mali.so
[ 01-13 17:31:39.060 1942: 1942 E/ ]
Device driver API match
Device driver API version: 23
User space API version: 23
[ 01-13 17:31:39.070 1942: 1942 E/ ]
mali: REVISION=Linux-r3p2-01rel3 BUILD_DATE=Fri Mar 21 13:52:50 KST 2014
[ 01-13 17:31:39.070 1939: 1939 W/InterfaceController ]
Error (undefined symbol: net_iface_send_command_fini) while searching for the interface command fini function
[ 01-13 17:31:39.075 1937: 1982 D/Vold ]
Volume sdcard1 state changing 0 (No-Media) -> 2 (Pending)
[ 01-13 17:31:39.075 1937: 1982 D/DirectVolume ]
DirectVolume::handlePartitionAdded -> MAJOR 179, MINOR 17, PARTN 1

I don't know if that helps, but it's pretty much identical on 5.1.1 (5.1.1 also shows "couldn't find audio_conf.txt" and "Audio service is not initiated.") The efs1.mbn error stands out to me but then I have no idea what any of this means, so it could be nothing.

Restoring the Nandroid backup of the stock 4.3 ROM the phone came with works fine, boots etc. I've tried restoring only the EFS from that backup after installing SlimLP in case that helped, but no dice, same error.

So, what am I missing? Probably something basic, it's been over a year since I last flashed a new ROM to anything, but it's driving me nuts.