[Galaxy S 4 i9505 Original Android Development] yfriday14:
There is no /cache/multiboot/ directory.

I found only /raw/cache/multiboot.

EDIT1: I am not able to boot CM13 and Resurrection Remix M v5.7.4, but I was able to boot two instances of MIUI V5.

EDIT2: Added another log as attachment, after switching and rebooting to Resurrection Remix M v5.7.4.

EDIT3: I found the following errors in the last_kmsg log related to extsd-slot-rr573 slot.

[ 9.525939] mblog: ROM ID is: extsd-slot-rr573
[ 9.526214] mblog: fstab: /dev/block/platform/msm_sdcc.1/by-name/boot /boot emmc defaults recoveryonly
[ 9.526397] mblog: fstab: /dev/block/platform/msm_sdcc.1/by-name/recovery /recovery emmc defaults recoveryonly
[ 9.526611] mblog: fstab: /dev/block/platform/msm_sdcc.1/by-name/system /system ext4 ro,barrier=1,errors=panic wait
[ 9.526824] mblog: -> /system entry
[ 9.526916] mblog: fstab: /dev/block/platform/msm_sdcc.1/by-name/apnhlos /firmware vfat ro,shortname=lower,uid=1000,gid=1000,dmask=227,fmask=337,context=u:object_r:firmware_file:s0 wait
[ 9.527069] mblog: fstab: /dev/block/platform/msm_sdcc.1/by-name/mdm /firmware-mdm vfat ro,shortname=lower,uid=1000,gid=1000,dmask=227,fmask=337,context=u:object_r:firmware_file:s0 wait
[ 9.527313] mblog: fstab: /dev/block/platform/msm_sdcc.1/by-name/efs /efs ext4 nosuid,nodev,noatime,noauto_da_alloc,journal_async_commit,errors=panic wait,check,notrim
[ 9.527526] mblog: fstab: /dev/block/platform/msm_sdcc.1/by-name/cache /cache f2fs nosuid,nodev,noatime,rw,inline_xattr wait,check,formattable
[ 9.527679] mblog: -> /cache entry
[ 9.527801] mblog: fstab: /dev/block/platform/msm_sdcc.1/by-name/cache /cache ext4 nosuid,nodev,noatime,noauto_da_alloc,journal_async_commit,errors=panic wait,check,formattable
[ 9.527954] mblog: -> /cache entry
[ 9.528106] mblog: fstab: /dev/block/platform/msm_sdcc.1/by-name/userdata /data f2fs nosuid,nodev,noatime,rw,inline_xattr wait,check,formattable,encryptable=footer
[ 9.528320] mblog: fstab: /dev/block/platform/msm_sdcc.1/by-name/userdata /data ext4 nosuid,nodev,noatime,noauto_da_alloc,journal_async_commit,errors=panic wait,check,formattable,encryptable=footer
[ 9.528472] mblog: fstab: /devices/platform/msm_sdcc.2/mmc_host/mmc2* auto auto defaults voldmanaged=sdcard1:auto,encryptable=userdata
[ 9.528717] mblog: -> External SD entry
[ 9.528839] mblog: fstab: /devices/platform/msm_hsusb_host/usb* auto auto defaults voldmanaged=usb:auto
[ 9.529022] mblog: /raw/system: Has 1 fstab entries
[ 9.529174] mblog: Attempting to mount(/dev/block/platform/msm_sdcc.1/by-name/system, /raw/system, ext4, 1, barrier=1,errors=panic)
[ 9.529327] mblog: /dev/block/platform/msm_sdcc.1/by-name/system: Waiting up to 20 seconds for block device
[ 9.539550] EXT4-fs (mmcblk0p16): mounted filesystem with ordered data mode. Opts: barrier=1,errors=panic
[ 9.539703] mblog: Successfully mounted /dev/block/platform/msm_sdcc.1/by-name/system (ext4) at /raw/system
[ 9.539794] mblog: /raw/cache: Has 2 fstab entries
[ 9.539978] mblog: Attempting to mount(/dev/block/platform/msm_sdcc.1/by-name/cache, /raw/cache, f2fs, 1030, inline_xattr)
[ 9.540100] mblog: /dev/block/platform/msm_sdcc.1/by-name/cache: Waiting up to 20 seconds for block device
[ 9.540710] F2FS-fs (mmcblk0p18): Magic Mismatch, valid(0xf2f52010) - read(0x20680)
[ 9.540771] F2FS-fs (mmcblk0p18): Can't find valid F2FS filesystem in 1th superblock
[ 9.541198] F2FS-fs (mmcblk0p18): Magic Mismatch, valid(0xf2f52010) - read(0x0)
[ 9.541351] F2FS-fs (mmcblk0p18): Can't find valid F2FS filesystem in 2th superblock
[ 9.541412] F2FS-fs (mmcblk0p18): Magic Mismatch, valid(0xf2f52010) - read(0x20680)
[ 9.541564] F2FS-fs (mmcblk0p18): Can't find valid F2FS filesystem in 1th superblock
[ 9.541687] F2FS-fs (mmcblk0p18): Magic Mismatch, valid(0xf2f52010) - read(0x0)
[ 9.541809] F2FS-fs (mmcblk0p18): Can't find valid F2FS filesystem in 2th superblock
[ 9.542388] mblog: Failed to mount /dev/block/platform/msm_sdcc.1/by-name/cache (f2fs) at /raw/cache: Invalid argument
[ 9.542541] mblog: Attempting to mount(/dev/block/platform/msm_sdcc.1/by-name/cache, /raw/cache, ext4, 1030, noauto_da_alloc,journal_async_commit,errors=panic)
[ 9.542663] mblog: /dev/block/platform/msm_sdcc.1/by-name/cache: Waiting up to 20 seconds for block device
[ 9.546874] EXT4-fs (mmcblk0p18): mounted filesystem with ordered data mode. Opts: noauto_da_alloc,journal_async_commit,errors=panic
[ 9.547058] mblog: Successfully mounted /dev/block/platform/msm_sdcc.1/by-name/cache (ext4) at /raw/cache
[ 9.547180] mblog: 1 fstab entries for the external SD
[ 9.547363] mblog: [Attempt 1/10] Finding and mounting external SD
[ 9.547515] mblog: Matching devices against pattern: /devices/platform/msm_sdcc.2/mmc_host/mmc2*
[ 9.550750] mblog: /default.prop contains fuse-exfat override: false
[ 9.641510] mblog: Using fuse-exfat: 0
[ 9.641723] mblog: Failed to mount /dev/block/mmcblk1p1 (exfat) at /raw/extsd: No such device
[ 9.641906] mblog: Failed to mount /raw/extsd
[ 9.642028] mblog: Failed to mount fstab

The partitions file contains this:

/dev/block/mmcblk0p29 /data ext4 rw,seclabel,relatime,data=ordered 0 0
/dev/block/mmcblk0p29 /sdcard ext4 rw,seclabel,relatime,data=ordered 0 0
/dev/block/mmcblk0p18 /cache ext4 rw,seclabel,relatime,data=ordered 0 0
/dev/block/mmcblk1p1 /external_sd fuseblk rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other,max_read=131072,blksize=4096 0 0
/dev/block/mmcblk0p16 /system ext4 rw,seclabel,relatime,data=ordered 0 0

So

mmcblk0p16 /system was mounted successfully as ext4.

mmcblk0p18 /cache was mounted successfully as ext4.

mmcblk1p1 /external_sd fuseblk: Failed to mount /dev/block/mmcblk1p1 (exfat) at /raw/extsd: No such device

Strange anyway, as after booting into MIUI v5 (Kitkat based), I can see and use the external sd.