[Galaxy S 4 i9505 Original Android Development] jthetzel:
TWRP-2.8.6.0-F2FS cannot mount the data partition for my i9505g ("E:Unable to mount '/data'"). This complicates converting the partition to F2FS (though a workaround is to use Philz to convert the partitions and then TWRP to install CM12.1) and introduces numerous error messages while in recovery. I believe the problem stems from differences in partitioning in Google's i9505g compared with the other Samsung S4 Qualcomm variants (userdata is mmcblk0p28 on i9505g but mmcblk0p29 on i9505). While I could not find the relevant files on AntaresOne's github repositories, I believe changing the partition paths to the by-name convention should correct this:

BoardConfig.mk

-TW_CRYPTO_REAL_BLKDEV := "/dev/block/mmcblk0p29"
+TW_CRYPTO_REAL_BLKDEV := "/dev/block/platorm/msm_sdcc.1/by-name/userdata

recovery.fstab

-/boot emmc /dev/block/mmcblk0p20
-/cache ext4 /dev/block/mmcblk0p18
-/data ext4 /dev/block/mmcblk0p29
-/recovery emmc /dev/block/mmcblk0p21
-/system ext4 /dev/block/mmcblk0p16
-/efs ext4 /dev/block/mmcblk0p10 flags=display="EFS";backup=1
+/boot emmc /dev/platform/msm_sdcc.1/by-name/boot
+/cache auto /dev/platform/msm_sdcc.1/by-name/cache
+/data auto /dev/platform/msm_sdcc.1/by-name/userdata
+/recovery emmc /dev/platform/msm_sdcc.1/by-name/recovery
+/system auto /dev/platform/msm_sdcc.1/by-name/system
+/efs ext4 /dev/platform/msm_sdcc.1/by-name/efs flags=display="EFS";backup=1

(Is changing filesystem type to auto advantageous as we don't know if it will be ext4 or f2fs?)

Just for reference, here is a list of parition differences between the i9505 and i9505g.

i9505
backup -> /dev/block/mmcblk0p23
boot -> /dev/block/mmcblk0p20
carrier -> /dev/block/mmcblk0p28
fota -> /dev/block/mmcblk0p22
fsg -> /dev/block/mmcblk0p24
hidden -> /dev/block/mmcblk0p27
param -> /dev/block/mmcblk0p19
persdata -> /dev/block/mmcblk0p26
recovery -> /dev/block/mmcblk0p21
ssd -> /dev/block/mmcblk0p25
userdata -> /dev/block/mmcblk0p29

i9505g
backup -> /dev/block/mmcblk0p24
boot -> /dev/block/mmcblk0p21
carrier -> not present
fota -> /dev/block/mmcblk0p23
fsg -> /dev/block/mmcblk0p25
hidden -> not present
param -> /dev/block/mmcblk0p20
persdata -> /dev/block/mmcblk0p27
recovery -> /dev/block/mmcblk0p22
ssd -> /dev/block/mmcblk0p26
userdata -> /dev/block/mmcblk0p28

And for further reference, here is a list of all the internal partitions on the i9505g.

root@jgedlte:/dev # ls /dev/block/platform/msm_sdcc.1/by-name/ -al
total 0
drwxrwxr-x 2 system radio 600 May 5 20:53 .
drwxr-xr-x 4 root root 680 May 5 20:53 ..
lrwxrwxrwx 1 root root 20 May 5 20:53 aboot -> /dev/block/mmcblk0p6
lrwxrwxrwx 1 root root 20 May 5 20:53 apnhlos -> /dev/block/mmcblk0p1
lrwxrwxrwx 1 root root 21 May 5 20:53 backup -> /dev/block/mmcblk0p24
lrwxrwxrwx 1 root root 21 May 5 20:53 boot -> /dev/block/mmcblk0p21
lrwxrwxrwx 1 root root 21 May 5 20:53 cache -> /dev/block/mmcblk0p18
lrwxrwxrwx 1 root root 21 May 5 20:53 efs -> /dev/block/mmcblk0p10
lrwxrwxrwx 1 root root 21 May 5 20:53 fota -> /dev/block/mmcblk0p23
lrwxrwxrwx 1 root root 21 May 5 20:53 fsg -> /dev/block/mmcblk0p25
lrwxrwxrwx 1 root root 21 May 5 20:53 m9kefs1 -> /dev/block/mmcblk0p13
lrwxrwxrwx 1 root root 21 May 5 20:53 m9kefs2 -> /dev/block/mmcblk0p14
lrwxrwxrwx 1 root root 21 May 5 20:53 m9kefs3 -> /dev/block/mmcblk0p15
lrwxrwxrwx 1 root root 20 May 5 20:53 mdm -> /dev/block/mmcblk0p2
lrwxrwxrwx 1 root root 21 May 5 20:53 misc -> /dev/block/mmcblk0p19
lrwxrwxrwx 1 root root 21 May 5 20:53 modemst1 -> /dev/block/mmcblk0p11
lrwxrwxrwx 1 root root 21 May 5 20:53 modemst2 -> /dev/block/mmcblk0p12
lrwxrwxrwx 1 root root 20 May 5 20:53 pad -> /dev/block/mmcblk0p9
lrwxrwxrwx 1 root root 21 May 5 20:53 param -> /dev/block/mmcblk0p20
lrwxrwxrwx 1 root root 21 May 5 20:53 persdata -> /dev/block/mmcblk0p27
lrwxrwxrwx 1 root root 21 May 5 20:53 persist -> /dev/block/mmcblk0p17
lrwxrwxrwx 1 root root 21 May 5 20:53 recovery -> /dev/block/mmcblk0p22
lrwxrwxrwx 1 root root 20 May 5 20:53 rpm -> /dev/block/mmcblk0p7
lrwxrwxrwx 1 root root 20 May 5 20:53 sbl1 -> /dev/block/mmcblk0p3
lrwxrwxrwx 1 root root 20 May 5 20:53 sbl2 -> /dev/block/mmcblk0p4
lrwxrwxrwx 1 root root 20 May 5 20:53 sbl3 -> /dev/block/mmcblk0p5
lrwxrwxrwx 1 root root 21 May 5 20:53 ssd -> /dev/block/mmcblk0p26
lrwxrwxrwx 1 root root 21 May 5 20:53 system -> /dev/block/mmcblk0p16
lrwxrwxrwx 1 root root 20 May 5 20:53 tz -> /dev/block/mmcblk0p8
lrwxrwxrwx 1 root root 21 May 5 20:53 userdata -> /dev/block/mmcblk0p28