yashsingh1/xdaforums huggingface dataset:
[Galaxy S 4 General] robertobsc:
Hi Andrei, gn.

I was following the Perseus thread since it was created, but just now I installed your kernel.

I was extremely disgusted with Samsungs S4 performance, I just wanted to throw it from my window.

Now that I installed your kernel, just seems that I bought a new phone. It is completely amazing, the performance is outstanding, the transition effects practically without lags. It wasn't a bump, it was a new phone!

Just to say thanks to you. It Is remarkable how you alone can improve a phone that a whole Samsung developers team can't.

I'll give you the beer that you surely deserves, as soon as I can't do it tomorrow.

Cheers!
[Galaxy S 4 General] robertobsc:
Well... Nothing is completely perfect, is it?

I can't mount system as rw, it isn't working... I tried some solutions but didn't work. Had you guys this problem?

[EDIT]: I just bricked my phone... oh man thats fantastic... i installed philz recovery, installed busybox; Then mounted the system as rw, and i was capable to change the ro.secure to false. Then updated supersu and marked to enable root in boot. and then... the phone rebooted to a nice black screen... forever... oh man....

downloading a new room... terrible that i will lose my whole data.....
[Galaxy S 4 General] ktouy:
sorry for the delay

hope this is what you ask for..

now im on Paranoid 4.5 beta and still the same, also with front camera im facing cant connect to camera since paranoid 4.45 ...

Thanks!
[Galaxy S 4 General] ktouy:
Dont know if this is usefull but ive try gost log during the error here you have some screenshot.

Thanks!
[Galaxy S 4 General] :
Has anyone tried this Kernel with the Official Cyanogenmod 11 nightlies? what did you think? will it work?
[Galaxy S 4 General] robertobsc:
Hi [MENTION=4167023]AndreiLux[/MENTION]

If you can please, help me.

Its is the second time that my phone is soft bricked. All that is did was:

- Installed perseus

- installed philz

- updated super su binary when asked from its app

- changed the ro.secure.storagesupport to false.

It was working during the day quite nicely. Then I tried to reboot and there it goes again: it just doesnt boot anymore. Black screen after samsungs logo.

Seems that it happens when i change this storagesupport to false and reboot.

Do you know what is going on? Did I had to change any other setting with the storage support one?

I think i can get the logs via adb, cant i? What logs do you need me to send to you?

Please help me!!
[Galaxy S 4 General] HassanM:
Friends,

At times I keep getting this error in Synapse (Screenshot attached)...

Can anyone shed some light on it?

Thanks in advance. ..
[Galaxy S 4 General] ChapuLiNX:
Hi,

I was triying a few roms and kernels. .. the best rom was for me wanamlite v4 4.4.2..... and best kernel was perseus 19.1 ... the problem was when i try to use them at the same time.

The deep sleep issue apears..

So i try some troubleshoting and voila!

Some interesting things happend.

If i install perseus.. deactivate synapse install stock kernel.. and then reinstall perseus..... deep sleep looks fixed even with perseus kernel installed... then.. upgrade synapse and activate again... and works!

Wanamlite v4 4.4.2 with perseus deep sleep fixed and synapse working.

Tested for 5 days. Booting device...etc.

I hope this help for someone...
[Galaxy S 4 General] HassanM:
This thread seems to be dormant....
[Galaxy S 4 General] NZnewbie:
Dead as.... Pretty much how I expected it to go. Bummer.
[Galaxy S 4 General] A_Reflection:
Need help

I need some help with rolling back the kernel from Perseus Alpha 19. I'm using Kitkat 4.4.2 rom and I'm unable to work Wifi tethering, I have also read half of this topic and I find out that is a know issue. I saw the stock kernel file in this topic and I have download and replaced the boot.img file from Perseus kernel zip file and installed stock kernel by using clockwork mod, then I have wiped cache and wiped dalvik cache and rebooted. The problem is when loading the OS, number of programs are reduced and I was unable to see most of my applications including google store!. But when I install Perseus kernel again all my applications are working again. How can I roll back to my old stock kernel without wipe all user data or installing stock rom again. :(
[Galaxy S 4 General] HassanM:
Which rom r u using? I mean Stock or Custom???
[Galaxy S 4 General] VoLTaqe:
[MENTION=4167023]AndreiLux[/MENTION] Will you plan update kernel with latest source ?
[Galaxy S 4 General] HassanM:
Mate, this is pretty much a dead thread..... Andrei isn't seem to be around..... Although Im sure Andrei is very well aware of all the developments coming along but perhaps hes waiting for the significant one....
[Galaxy S 4 General] AndreiLux:
There's nothing new.
[Galaxy S 4 General] VoLTaqe:
What about problem on wifi tethering and charge problem when phone is closed not showing animation as 4.3 ?
[Galaxy S 4 General] powermax91:
MIUI now use TW 4.4.2 kitkat for their rom as base but its stuck on bootanimation.

Could you support it please?
[Galaxy S 4 General] zozoz13:
Why you dont update the kernel since 6 month ago?(CMIIW) Is there any problem? Or Perseus v19.1 is the latest?

Sorry for asking it, because i love this kernel very much..
[Galaxy S 4 General] farid993:
What about update linux version to 3.4.9x ?
[Galaxy S 4 General] farid993:
Hi [MENTION=4167023]AndreiLux[/MENTION]

I got this error over and over in logcat. Is it kernel related?

E/UsbDebuggingManager( 5084): Communication error:

10-06 15:03:10.805 E/UsbDebuggingManager( 5084): java.io.IOException: Connection refused

10-06 15:03:10.805 E/UsbDebuggingManager( 5084):	at android.net.LocalSocketImpl.connectLocal(Native Method)

10-06 15:03:10.805 E/UsbDebuggingManager( 5084):	at android.net.LocalSocketImpl.connect(LocalSocketImpl.java:287)

10-06 15:03:10.805 E/UsbDebuggingManager( 5084):	at android.net.LocalSocket.connect(LocalSocket.java:130)

10-06 15:03:10.805 E/UsbDebuggingManager( 5084):	at com.android.server.usb.UsbDebuggingManager.listenToSocket(UsbDebuggingManager.java:81)

10-06 15:03:10.805 E/UsbDebuggingManager( 5084):	at com.android.server.usb.UsbDebuggingManager.run(UsbDebuggingManager.java:117)

10-06 15:03:10.805 E/UsbDebuggingManager( 5084):	at java.lang.Thread.run(Thread.java:841)
[Galaxy S 4 General] AndreiLux:
No. Maybe your ROM or USB drivers on the PC.
[Galaxy S 4 General] AndreiLux:
I've recently got into possession of my own iPro2 photospectrometer so I revisited the calibration on my S4. To my surprise it was quite off from what Ryan had calibrated 1.5 years ago. Here's the results for the below calibration: http://imgur.com/a/wdDnX#0

For anybody interested/caring about colour accuracy, this would be new values you can setup in Synapse:

Chroma weight: 9
Red gain: 20
Green gain: 11
Blue gain: 15
Yellow gain: 19
Cyan gain: 10
Magenta gain: 9

Red: #FF131A
Green: #55FF00
Blue: #1A1EFF
Yellow: #FFEF08
Cyan: 2AF0FF
Magenta: #EE00FFF
White: #FFF1F7
[Galaxy S 4 General] cmd512:
Looking good, thanks!
[Galaxy S 4 General] VoLTaqe:
Anyone add doubletaptowake option with this commit ?

https://github.com/piasek1906/Piasek-KK/commit/2d5a529eb0febc3821b8cbb541bab08be7ffef90

I want try but i dont have linux system
[Galaxy S 4 General] jotade:
Hi everyone, is there a way to fix WiFi Tethering with this kernel? Thanks
[Galaxy S 4 General] VoLTaqe:
No.
[Galaxy S 4 General] Unix_Dominator:
Perseus Kernel for (TW Roms)Android 5.0.1(GT-I9500)

I would just like to ask if Perseus Kernel will be available to Touchwiz Android 5.0.1 ?

Cause as of now after updating and using the phone the battery pretty much sucks it at least used to give me a full day use but now after updating it only give me around 5 hours :( which something that i dont like.

I also know that the Lollipop source isn`t released by Samsung so it will be a tough time to work on Exynos 5410 based processor.

If it is possible to create an AOSP kerenel i am also fine with that.

Thanks,

Ashen
[Galaxy S 4 General] zetlaw:
Thats not true.

Use romswitcher kernel. Its perseus but without overclocking.
[Galaxy S 4 General] MemAllocatoR:
[MENTION=4167023]AndreiLux[/MENTION]

Please bring back to life our device with latest lollipop kernel source code that has been released now...

http://opensource.samsung.com/reception/receptionSub.do?method=sub&sub=F&searchValue=GT-I9500

Page number 3. Thanks
[Galaxy S 4 General] AndreiLux:
I'll look into it but I have a lot of stuff to do before I can get back to the S4.
[Galaxy S 4 General] roysky007:
Hi [MENTION=4167023]AndreiLux[/MENTION]

which Kitkat bootloader do you have on your S4?

I seem the have this drain with the perseus kernel discussed in the past pages. Edited the build.prop according to [MENTION=1984051]cmd512[/MENTION].

Running Omega latest Kitkat, but my bootloader is still BMG9.

I read the past pages but nothing mentioned about which Kitkat bootloader version.

sorry to bring up an old post, and thank you for this awesome kernel!
[Galaxy S 4 General] bala_gamer:
it shows 2ghz because its the max capable clock our s4 can acheive :) . mobile boots @ 700mhz without issues, but once u start stressing it via some becnhies it will get stuck
[Galaxy S 4 General] Xphoid:
tell me how to stress? antutu 3d, egypt 2.5 hd onscreen... ? what shall i do i did all of them and my fps is always between 38-40 whether GPU is at default or 700 or between somewhere...

Edit: if i set CPU clock to 1700 with android tuner, than it shows 1700 on antutu also... than i uninstalled android tuner and with only stweaks again showed wrong value @ 2000... i guess it actually should show current clock value instead of max capability...
[Galaxy S 4 General] bala_gamer:
Yes Egypt hd @ 700mhz will do

Btw, looks like I have enabled power saving mode long back, I didn't even noticed the difference anywhere lol. Now testing again
[Galaxy S 4 General] Xphoid:
but it doesnt do anything wrong with me and fps is at 38 or 40 as i told... and pls also have a loot at my editted message previously :) you are fast in response :)
[Galaxy S 4 General] mw86:
Boys I have great results, proof they are working.

(A15)

480mhz @ 1200mhz min

600mhz @ 1200mhz min

640mhz @ 1200mhz min run 1

640mhz @ 1200mhz min run 2

640mhz @ 1400mhz min run 1
[Galaxy S 4 General] mw86:
So we have a comparison of peak gpu all on stock perseus before gpu or cpu overclock added.

About 10,800 gpu Antutu

http://db.tt/G4Fe7nax

Edit: this is a stock run, but I realized your post said 3d now. I understand now. But with the oc i think you found at least a 100 points more in 3d :) the boost is definitely working.
[Galaxy S 4 General] AndreiLux:
It's an idiotic habit that has grown from incompetent developers thinking they are actually changing something. 95% of all changes in Linux minor versions don't even affect your specific device.
[Galaxy S 4 General] acidmoder:
Thank you so much AndreiLux! Version 4 is running rock solid on my S4.

No overheating, no camera issues and deep sleeping just fine and quick! :cool:

Flashed over a stock (rooted) MEA ROM

Cheers!

André
[Galaxy S 4 General] mw86:
+1 outstanding work! Andrei, thanks for explaining about the linux kernels :) :good:
[Galaxy S 4 General] Xphoid:
Hangouts mate!!
[Galaxy S 4 General] Tvercetti28:
I have sucessfully oc my GPU to 640mhz and got a nice score over 7000 in 3D Mark extreme benchmark, so oc is definitetly working .
[Galaxy S 4 General] skivnit:
Voltages ?
[Galaxy S 4 General] HassanM:
What're u using to OC your GPU???

Thanks
[Galaxy S 4 General] mw86:
Stweaks latest perseus kernel. He posted 3dmark extreme results and a bit above is mine on the standard test.
[Galaxy S 4 General] HassanM:
I see... I currently have 3.4 w/ Stweaks

I suppose 3.4 doesn't have this option so far...

Thanks anyway
[Galaxy S 4 General] mw86:
Just grab his latest :)

4.0

https://github.com/AndreiLux/Perseus-UNIVERSAL5410/wiki
[Galaxy S 4 General] Tvercetti28:
Well on 640Mhz step i have undervolted -50 mv and below steps -075, and its running perfectly stable.
[Galaxy S 4 General] stanley08:
Well, for some reason... The kernel is getting worse for me.

v3.2 - Working good. Always has sound

v3.4 - Partial sound (works after restart)

v4.0 - No Sound whatsoever, no matter number of restarts or even taking out the battery...
[Galaxy S 4 General] croach246:
Have a concern regarding CPU voltages (not gpu guys sorry). As Bala pointed out to me earlier in the thread, STweaks settings won't reflect on a third party app vicversa - I'm now using Android settings as the third party app.

Is it best to only have one or the other?

2nd: I had set the minimum cpu freq. To 100MHz when screen off using Android tuner. Now, STweaks does not allow voltage control for freq. Below 200MHz, while android tuner allows voltage controls down to 100MHz.. Is this a safety feature in STweaks?
[Galaxy S 4 General] bala_gamer:
happened to me once on 4.0, switch off, pull out battery ,put it back after few mins, it got fixed
[Galaxy S 4 General] Xphoid:
At last I found my stable voltages for GPU... And see that GPU controls are actually working... Thanks to [MENTION=4745870]mw86[/MENTION]...

I could see that GPU is working only by setting min CPU freq to 1200 or 1400 and my stable daily max is 1700 (all CPU freqs –100 UV'd)

And GPU UV;

-50mV @ 700MHz

-62.5mV @ 640MHz

-75mV @ 600MHz

-100mV @ rest of the freqs.

And I did all the benchmark tests (3D Mark. Several things in GFX Benchmarks incl. Egypt 2.5, Quadrant, etc...) without any reboots, SODs, etc... (cpu @ min 1400 & max 1700)

So everything seems normal...

My question is it safe to go on with

GPU @ 700MHz for a daily usage (CPU @ 100MHz min & 1.7GHz max) with the above UV values?

PS: Sound bug never happened to me on alpha 4 and my camera app opening & shooting a photo time is as it should be...
[Galaxy S 4 General] gdonanthony:
when changing GPU settings does it apply instantly or it needs reboot ?
[Galaxy S 4 General] hathara:
Sound problem

When sound isnot working for me get back i just need turn volume down all sound turn off my galaxy s4 and turn on

---------- Post added at 10:27 AM ---------- Previous post was at 10:22 AM ----------

can you pls upload your stewask profile?
[Galaxy S 4 General] jlevy73:
If changing from STweaks, press apply and you're all set.
[Galaxy S 4 General] skivnit:
For some reason my phone can't even stay stable on - 50mv cpu undervolt how's that possible
[Galaxy S 4 General] Xphoid:
and how can i do that? :) i didnt know there is a profile file...

tough i wouldnt recommend using some other devices settings since all chips are not equal... you better find stable values for you own device...
[Galaxy S 4 General] hathara:
stewaks profiles

look this post about a app who save profiles in stewaks

http://xdaforums.com/showthread.php?t=2034981
[Galaxy S 4 General] Xphoid:
oh great :good:

thanx for the heads up, didnt aware of it... and it works with S4, right?
[Galaxy S 4 General] aydink_1903:
Please lets share /data/.perseus/default.profile like that

internal_read_ahead_kb=256

sd_read_ahead_kb=1024

internal_iosched=cfq

internal_iosched=cfq

digital_abs_headphone_left=0

digital_abs_headphone_right=0

CONFIG_BOOTED=true

CONTROLSWITCH_CPU=on

scaling_max_freq=1600000

scaling_min_freq=200000

CPU_VOLT_2000=1225000

CPU_VOLT_1900=1200000

CPU_VOLT_1800=1175000

CPU_VOLT_1700=1125000

CPU_VOLT_1600=1100000

CPU_VOLT_1500=1075000

CPU_VOLT_1400=1025000

CPU_VOLT_1300=1000000

CPU_VOLT_1200=950000

CPU_VOLT_1100=925000

CPU_VOLT_1000=875000

CPU_VOLT_900=850000

CPU_VOLT_800=825000

CPU_VOLT_600=1150000

CPU_VOLT_550=1100000

CPU_VOLT_500=1025000

CPU_VOLT_450=1000000

CPU_VOLT_400=987500

CPU_VOLT_350=975000

CPU_VOLT_300=950000

CPU_VOLT_250=925000

CPU_VOLT_200=900000

CPU_VOLT_150=875000

CPU_VOLT_100=850000

CONTROLSWITCH_GPU=on

sgx_dvfs_max_lock=640

GPU_VOLT_700=1150000

GPU_VOLT_640=1125000

GPU_VOLT_600=1100000

GPU_VOLT_532=1075000

GPU_VOLT_480=1037500

GPU_VOLT_350=925000

GPU_VOLT_266=900000

GPU_VOLT_177=900000

hook_intercept=off

sequence_intercept=off

brightness_reduction=75

brightness_takeover_point=30

brightness_input_delta=20

s_edge_enhancement=off

de_positive_e=0

de_positive_f=0

de_positive_b=0

cs_weight=0

cs_red=0

cs_green=0

cs_blue=0

cs_yellow=0

cs_cyan=0

cs_magenta=0

scr_white_red=0

scr_white_green=0

scr_white_blue=0

switch_hp_mono=off

digital_speaker_volume=6

digital_earpiece_volume=6

switch_sp_privacy=off

switch_eq_speaker=on

switch_eq_headphone=on

eq_hp_gain_1=12

eq_hp_gain_2=-9

eq_hp_gain_3=4

eq_hp_gain_4=-10

eq_hp_gain_5=0

sd_iosched=cfq

vnswap_size=0

max_pool_percent=20

swappiness=60

Regards

GT-I9500 cihazımdan Tapatalk 4 Beta ile gönderildi
[Galaxy S 4 General] hathara:
app backup

i not sure if works on s4 never test!

if you can test and shared with us if is working!
[Galaxy S 4 General] jianlinooi:
so 640mhz gpu is stable with UV ...with UV 1.6ghz cpu?
[Galaxy S 4 General] croach246:
I had some trouble when UV and forcing the cpu to 100MHz when screen off - would shut down by itself. I'm now UV - 75mV, but have kept the voltages of 100, 150, 200MHz stock (or - 25mV can't remember) and disabled "force cpu when screen off". been 12 hrs now and no trouble as yet. Maybe try that?

-using Android tuner btw

---------- Post added at 11:53 PM ---------- Previous post was at 11:51 PM ----------

Also STweaks Profiles - available from play store - another great app for saving, swapping and exporting STweaks Profiles.
[Galaxy S 4 General] acidmoder:
I heard that Samsung has decreased the CPU thermal throttle from 100C to 76C on the latest firmwares (MF8?). I am on MEA + Perseus 4 and according to few tests I've done, my S4 is throttling at 90C (despite setting boost_mode to 1).

I was wondering if, when you flash Perseus over MF8, it keeps throttling at 90C? Has anyone tested it?

EDIT: actually I read about the new thermal throttle here: http://xdaforums.com/showthread.php?t=2268569&page=144 (post #1433)
[Galaxy S 4 General] bala_gamer:
I don't think we need a throttle at 76c, even though it's not going to affect any real world performance I would like to stick with the throttle limit of the hardware rather than Samsung enforced throttle.
[Galaxy S 4 General] acidmoder:
Agree! I'd rather be throttling at 100C if possible. That's why I have raised that question. I guess Perseus (at least so far on v4) will overrule original firmware settings to allow the temp to reach 90C before throttling. Am I right?
[Galaxy S 4 General] noideaforusername:
I flashed this kernel yesterday and have a few questions:

1. I never overclocked or touched anything in the CPU but when I ran Antutu it shows 2000mHz.

2. The default GPU clock is 480mHz? I was sure it was 532mHz.

3. If someone can guide me how to undervolt the CPU the best way so I won't lose any performance I'll be most thankful.

Thanks for your help and thanks Anderi for the excellent kernel :)
[Galaxy S 4 General] mw86:
Here is why gpu at 480mhz. Samsung lied to users and unless a benchmark is ran stock runs 480mhz. The 533 loads only in benchmarks. The following is the direct change log on github. Andrei wrote us a very nice write up and provides a link with more infos.

Perseus alpha4 (04/07):

GPU overclocking and voltage control.

Controls to be found in STweaks or alternatively via /sys/devices/platform/pvrsrvkm.0/. There is no minimum frequency because userspace drivers are dynamically changing the min frequency depending on scenario. 267MHz is minimum for 2D work for better efficiency and race-to-idle as the whole GPU gets power gated during runtime. The 267MHz step is also special as it has its own separate fixed voltage (900mV), during 2D work, if the GPU never switches DVFS state, it will never change this voltage and undervolting will have no effect.

Before anybody asks why 480MHz is the default max clock, I've already discussed and explained it here. http://forum.beyond3d.com/showthread.php?p=1760026#post1760026

Disabled GPU CPU QoS requests (CPU min locked at 600MHz virtual on => 480MHz GPU).

Updated ISP kernel drivers. Camera libraries should be updated to => MF3 versions. Here's a CWM for the reverse-fix.

Added ZSwap to the kernel with a VNSwap device, uses Snappy compression instead of LZO. Configurable via STweaks.

Added improved Android-style lowmemorykiller logic.

Various miscellaneous changes from updated sources can be viewed here.
[Galaxy S 4 General] HassanM:
I did try 4 but reverted to 3.4... I think we should all wait until the official code is released by Samsung ... Until that time we should stick to what's available and keeping our phones fully functional without any bugs/glitches....
[Galaxy S 4 General] cmd512:
What on earth are you talking about, sources have been released by Samsung already... that's why the latest camera firmware works!

I have no issues with sound on alpha4, only issue I have is a very laggy / delayed camera. But, I think this has more with the tweaked LMK and / or zSwap updates than anything else.

Again, has nothing to do with "official code."
[Galaxy S 4 General] gdonanthony:
got no camera lag ... its fast when opening like 1-2 secs...
[Galaxy S 4 General] skivnit:
Anyone experiencing random reboots? Trying to narrowing the causes down. I'm using Wanam's Rom with latest perseus
[Galaxy S 4 General] beatsmaster0510:
Also experiencing this. Have no time to find the cause though.
[Galaxy S 4 General] hotheabilly:
No camera issues and slowdown when opening app.
[Galaxy S 4 General] skivnit:
Never had a reboot problem until few days ago. How can I get a log of what's causing it
[Galaxy S 4 General] mw86:
Your reporting without undervolt, right? Can't report unless this is true. If not restore stock volts to be sure.
[Galaxy S 4 General] mw86:
Same on mine im using these maxed out and still no camera lag.

I also use a separate mod for a swap in cache and data, each of those 250mb. I used to use ram manager but i reverted my setting to make use of the current new lmk values. It's been running smooth and camera opens very fast for me about under 2secs and phone app opens very fast. Only thing i set different is the system swapiness value I also set to 100 swapiness. I still don't see much ise of swap while using the phone but more so the kernel vswap seems to get maybe 70mb usage sometimes.

On my original settings I had camera lag before using all I described above, but it was my own settings which was the hinderence. I am back to using stock high freq zpne, up step level b and L and etc.

It may just be something simple for you guys causing lag?
[Galaxy S 4 General] skivnit:
All default no uv or oc
[Galaxy S 4 General] mw86:
Thank you. Just was checking for extra details.
[Galaxy S 4 General] hathara:
guide overclock

Bala_gamer do you will make a guide about overclock and undervolt s4 like you did on s3?

i really love that guide!
[Galaxy S 4 General] mw86:
I think last Dmesg is the only thing that shows on a reboot and may not show a log for it every time.
[Galaxy S 4 General] Paolonicus:
Tried using Pleasant For Ears EQ settings but it didn't help with the hissing noise. Though I noticed something else related with that hissing sound.

1. You would hardly notice this on loud, party like music. Try it with some instrumentals or songs with softer tone.

2. Not all of my mp3 has this hissing sound, even if there was a delay with the intro music.
[Galaxy S 4 General] bala_gamer:
sure, why not.
[Galaxy S 4 General] acidmoder:
Has anyone tried Alpha 5 yet? Running stable at A7 Max Freq = 650 MHz. Now, how can I be sure while running stress tests I am using mostly the A7 core and not the A15?

I am setting CPU MAX = 1300 MHz and carrying it on? In this case couldn't A15s be doing the job instead? Is there a way to select the core in use?

:confused:

Thanks!
[Galaxy S 4 General] beatsmaster0510:
i tried it too. Here my settings currently:

CPU MAX frequency: 1700 mhz

A7 MAX frequency: 650 mhz

Freq steps on both cores: - 50mV UV on all steps

GPU MAX frequency: 600 mhz

GPU core steps: -50mV UV