[Galaxy S 4 i9505 Android Development] robcore:
Lol you said it, the worst that could happen is a boot loop, but more like a bootloop of one. I'll put it into perspective, here is what machinex does on every boot:

#!/system/bin/sh

export PATH=${PATH}:/sbin:/system/bin:/system/xbin;[COLOR=DeepSkyBlue] //this exports these folders to your path[/COLOR]
BB=busybox [COLOR=DeepSkyBlue]//this alias' $BB as busybox[/COLOR]

$BB mount -o remount,rw -t auto /
$BB mount -t rootfs -o remount,rw rootfs
$BB mount -o rw,remount /system[COLOR=DeepSkyBlue] these mount your root and system partitions[/COLOR]

#Supersu
/system/xbin/daemonsu --auto-daemon & [COLOR=DeepSkyBlue]//this starts the su daemon nice and early[/COLOR]

#Busybox if Necessary
if [ ! -e /system/xbin/busybox ]; [COLOR=DeepSkyBlue]//this section installs busybox if it's not found in your xbin[/COLOR]
then
cp -p /sbin/busybox /system/xbin/busybox
chmod 755 /system/xbin/busybox
chown 0:0 /system/xbin/busybox
su -c "busybox --install -s /system/xbin"
fi;

# Make internal storage directory, and copy profiles to it.
if [ ! -d /data/.machinex ]; then[COLOR=DeepSkyBlue]//this section creates the kernel folder in data if it doesn't already exist[/COLOR]
mkdir /data/.machinex/;
$BB chmod -R 0777 /data/.machinex/;
fi;

if [ ! -d /sdcard/machinex ]; then[COLOR=DeepSkyBlue]//this section creates the sdcard/synapse folder if itdoesn't already exist[/COLOR]
mkdir /sdcard/machinex;
mkdir /sdcard/machinex/Synapse;
mkdir /sdcard/machinex/Logs;
fi;

if [ ! -e /data/.machinex/bck_prof ]; then[COLOR=DeepSkyBlue]//these lines all move profile files from res to data if they don't already exist[/COLOR]
cp -p /res/synapse/files/bck_prof /data/.machinex/bck_prof;
fi;

if [ ! -e /data/.machinex/dropcaches_prof ]; then
cp -p /res/synapse/files/dropcaches_prof /data/.machinex/dropcaches_prof;
fi;

if [ ! -e /data/.machinex/gammafaux_prof ]; then
cp -p /res/synapse/files/gammafaux_prof /data/.machinex/gammafaux_prof;
fi;

if [ ! -e /data/.machinex/gammafrancoN5_prof ]; then
cp -p /res/synapse/files/gammafrancoN5_prof /data/.machinex/gammafrancoN5_prof;
fi;

if [ ! -e /data/.machinex/gammafranco_prof ]; then
cp -p /res/synapse/files/gammafranco_prof /data/.machinex/gammafranco_prof;
fi;

if [ ! -e /data/.machinex/gamma_prof ]; then
cp -p /res/synapse/files/gamma_prof /data/.machinex/gamma_prof;
fi;

if [ ! -e /data/.machinex/gs4.sh ]; then
cp -p /res/synapse/files/gs4.sh /data/.machinex/gs4.sh;
fi;

if [ ! -e /data/.machinex/lmk_prof ]; then
cp -p /res/synapse/files/lmk_prof /data/.machinex/lmk_prof;
fi;

if [ ! -e /data/.machinex/hotplug_prof ]; then
cp -p /res/synapse/files/hotplug_prof /data/.machinex/hotplug_prof;
fi;

if [ ! -e /data/.machinex/spcm_prof ]; then
cp -p /res/synapse/files/spcm_prof /data/.machinex/spcm_prof;
fi;

# Backup mpdecision, powerhal, thermald and thermal-engine bs.
# They are useless for this kernel, but the user will require
# them otherwise.
[COLOR=DeepSkyBlue]//these backup system executable that interfere with kernel control over power and cpu function
, and renders them useless (the uninstaller script restores them, permissions and all, which is why i'm so adamanent about using the uninstaller script.
[/COLOR]if [ -e /system/lib/hw/power.default.so ]; then
mv /system/lib/hw/power.default.so /system/lib/hw/power.default.so.bak;
fi;

if [ -e /system/bin/thermal-engine ]; then
mv /system/bin/thermal-engine /system/bin/thermal-engine-bak;
fi;

if [ -e /system/bin/mpdecision ]; then
stop mpdecision;
mv /system/bin/mpdecision /system/bin/mpdecision-bak;
fi;

if [ -e /system/bin/thermald ] ; then
stop thermald
mv /system/bin/thermald /system/bin/thermald-bak;
fi;

sleep 5
[COLOR=DeepSkyBlue]//these set values that are already set in the kernel space, but I have ocd and a "measure twice, cut once," mentality, so they are a "just in case."[/COLOR]
#ensure proper default settings are selected (ramdisks can be finicky)
$BB echo 512 > /sys/block/mmcblk0/queue/read_ahead_kb;
$BB echo 512 > /sys/block/mmcblk1/queue/read_ahead_kb;
$BB echo 0 > /sys/class/power_supply/battery/wc_enable;
$BB echo 450000000 > /sys/class/kgsl/kgsl-3d0/max_gpuclk;
$BB echo 0 > /sys/module/msm_mpdecision/parameters/enabled;
$BB echo 1 > /sys/kernel/alucard_hotplug/hotplug_enable;
$BB echo 1 > /sys/module/msm_thermal/core_control/enabled;
$BB echo 1 > /sys/module/msm_thermal/parameters/enabled;
$BB echo 65 > /sys/module/msm_thermal/parameters/core_limit_temp_degC
$BB echo 55 > /sys/module/msm_thermal/parameters/limit_temp_degC
$BB echo 0 > /sys/module/msm_otg/parameters/otg_hack_enable;
$BB echo 2 > /sys/kernel/fast_charge/force_fast_charge;
$BB echo 2100 > /sys/kernel/fast_charge/ac_charge_level;
$BB echo 0 > /sys/kernel/fast_charge/screen_on_current_limit;
$BB echo 0 > /sys/kernel/fast_charge/failsafe;
#$BB echo 0 > /sys/kernel/fast_charge/use_mtp_during_fast_charge;
$BB echo 0 > /sys/kernel/sched/arch_power;
$BB echo 1 > /sys/kernel/sched/gentle_fair_sleepers;
$BB echo 1 > /proc/sys/kernel/sched_autogroup_enabled;
$BB echo 0 > /sys/devices/virtual/mdnie/mdnie/outdoor;
$BB echo 0 > /sys/devices/virtual/mdnie/mdnie/scenario;
$BB echo 0 > /sys/devices/virtual/mdnie/mdnie/mode;
$BB echo 1 > /sys/kernel/sound_control_3/gpl_sound_control_enabled
$BB echo "0 0 4294967295" > /sys/kernel/sound_control_3/gpl_speaker_gain [COLOR=DeepSkyBlue]//fun note, sound is neat, how has nobody commented on how awesome the latest faux sound is?//[/COLOR]
$BB echo "0 0 4294967295" > /sys/kernel/sound_control_3/gpl_headphone_gain
$BB echo "0 4294967295" > /sys/kernel/sound_control_3/gpl_cam_mic_gain
$BB echo "0 4294967295" > /sys/kernel/sound_control_3/gpl_mic_gain

# Init.d
$BB run-parts /system/etc/init.d [COLOR=DeepSkyBlue]//this runs init.d[/COLOR]

############################
# Alucard Touch Boost Settings
# For the future [COLOR=DeepSkyBlue]this will be used for an upgraded touch-boost driver setup one day when i feel like overhauling the drivers[/COLOR]
#$$BB echo 1350000 > /sys/module/alu_t_boost/parameters/input_boost_freq

# Synapse
$BB mount -t rootfs -o remount,rw rootfs [COLOR=DeepSkyBlue]//another just in case remount[/COLOR]

$BB echo "Custom" > /data/.machinex/gamma_prof;
$BB echo "Custom" > /data/.machinex/lmk_prof;
$BB echo "0" > /data/.machinex/volt_prof;
$BB echo "1" > /data/.machinex/dropcaches_prof; [COLOR=DeepSkyBlue]//these are more default settings[/COLOR]

# Google play services wakelock fix [COLOR=DeepSkyBlue]//this section was made by a fella whose name i forget, but he's a genius because you'll never get the google services wakelock issues, slim uses it too (actually slim and my post-init script are mostly the same, other than certain specifics//[/COLOR]
sleep 10
su -c "pm enable com.google.android.gms/.update.SystemUpdateActivity"
su -c "pm enable com.google.android.gms/.update.SystemUpdateService"
su -c "pm enable com.google.android.gms/.update.SystemUpdateService$ActiveReceiver"
su -c "pm enable com.google.android.gms/.update.SystemUpdateService$Receiver"
su -c "pm enable com.google.android.gms/.update.SystemUpdateService$SecretCodeReceiver"
su -c "pm enable com.google.android.gsf/.update.SystemUpdateActivity"
su -c "pm enable com.google.android.gsf/.update.SystemUpdatePanoActivity"
su -c "pm enable com.google.android.gsf/.update.SystemUpdateService"
su -c "pm enable com.google.android.gsf/.update.SystemUpdateService$Receiver"
su -c "pm enable com.google.android.gsf/.update.SystemUpdateService$SecretCodeReceiver"

$BB mount -o remount,ro -t auto /
$BB mount -t rootfs -o remount,ro rootfs [COLOR=DeepSkyBlue]//and we remount back into the ro state android expects[/COLOR]
$BB mount -o remount,ro /system

As you can see, the first boot is a pretty big adjustment process, with lots of files being moved around manually, etc. That's why it takes so long and is such an expensive operation, the initial setup.

Edit:fixed mega nevermind if you read about my mega failures before

Edit 2: to answer your question, yes you can still into recovery no problem. If it fails again just ensure you flash the recovery script. Also...not to bad mouth their hard work, but...I wouldn't use the sound mod again, some of those build prop lines are just downright dangerous:

audio.offload.gapless.enabled=true << BAD!

ro.config.hw_music_lp=true << BAD!

ro.config.music_lp_vol=true << BAD!

media.stagefright.use-awesome=false << BAD! REALLY BAD

audio.deep_buffer.media=true << BAD!

audio.offload.passthrough=false << BAD!

persist.service.bdroid.sap=true << unneeded

persist.audio.voice.clarity=on << BAD!

persist.dev.pm.dyn_samplingrate=1 << BAD!

lpa.releaselock=false << BAD!

Also, while I respect and love Albe and Slim and their awesome work, I would comment out or delete these lines in the future:

#boot.fps=(number)

#shutdown.fps=(number)

Also, how the heck are you surviving without a pc for a whole week? I would DIE!