yashsingh1/xdaforums huggingface dataset:
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] FranciscoAlefe:
[MENTION=8340552]jenslody[/MENTION] So could you replace the ROM launcher with a more compatible launcher ? it may even be the lawchair 2 you have in the Playstore
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] mubasshir330:
I used pixel launcher and I got a better and smoother experience so I would ask the developer to make Pixel launcher the default launcher.I think it would go well with the google boot animation and make it look pixelish.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] jenslody:
I'm not the rom developer and I don't have the capacities to maintain my own rom (I have a fulltime job and a private live).

And besides the time, I don't want to do any major changes to the rom, because I will probably try to get it official.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] jenslody:
I use Hacker's keyboard without any issues (I need a full blown PC-like keyboard sometimes).

Third party gallery apps can be installed, if you want it, I use Simple Gallery Pro.

You already have a lot theming settings in "Settings -> DerpQuest -> Design[ -> Themes]" and "Settings -> Display" and in lawnchair, if you use it.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] jenslody:
You can use whatever rom you like.

Feel free to build Bliss yourself (or stay with the version on my server).

I feel better with DerpFest (at the moment), that's why I build it.

I just share my builds with other users, because I have a j5nlte and my daughter and my son have j5xnlte and building and uploading for the other three devices is not too much work.

I can stop sharing my builds (and my trees) without issues for me and it would save me a lot of time and headaches.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] PhillipJC:
Thank you Jenslody for giving us a SELinux enforcing ROM.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] mubasshir330:
Great would love if this becomes official. Great Rom man! Thanks for supporting this old phone with the latest derpfest os :)
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] romgharti:
some people don't know other hard work and contribution. just complain about weak point and less features etc. we are lucky , we have legend developers for j5.

be mature and respect for our developers contributions.

i want to thanks [MENTION=8340552]jenslody[/MENTION] for felling alive on j5 community .
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] FranciscoAlefe:
[MENTION=8340552]jenslody[/MENTION] What is the difference between a ROM like bliss that is normal is this a ROM vanilla?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] jenslody:
DerpFest normally comes with gapps included, vanilla just means no gapps.

Bliss does not ship gapps in most cases, so it's already similar to vanilla derp.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] FranciscoAlefe:
OK
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] romgharti:
No ETA. You have to wait. when developer think, he will update according to need.

And do not post that can negative impact on developer 's feeling.

be mature.

thanks
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] fidaj:
Hello.

ROM on SM-J500H not loaded - loop logo screen...

i have TWRP version 3.3.1
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] amirizad_7436:
Clean flash?

And which rom you came from?

If it's stock it was marshmallow or lollipop??
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] ZHIWA-XM:
KTweak module is compatible with our device?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] romgharti:
yes, it is compatible. but if you got any problem you can disable from recovery also.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] fidaj:
ROM BootleggersROM-Queue4j53gxx.5.1-Stable-Shishufied-20200607-225906
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] jenslody:
Clean flash ?

/system and /data (without /data/media) ?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] fidaj:
Sorry, no.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] amirizad_7436:
Then do it
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] PhillipJC:
Running Derpfest with microg and Nova launcher. Good combination. ;)

Is their a way to pass the SafetyNet check?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] itachimendes:
Magisk + Edxposed!

install these modules:

-Hiddencore module: pass safetynet.

-CorePatch: to disable "apk signature verification, package manager signature verification."

-SudoHide: Hide app from others or "detach" app from playstore (hide vanced from playstore update)
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] PhillipJC:
Will install this modules later. Thank you. ?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] PhillipJC:
(SudoHide is not working).................... Got it working.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] PhillipJC:
SafetyNet check passed.?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] carlos974:
[MENTION=8340552]jenslody[/MENTION]

FYI

https://xdaforums.com/showpost.php?p=83374385&postcount=280
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] Zakaryan2004:
He knows that.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] ZHIWA-XM:
how install microg?

how uninstall bitgapps?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] Icker932:
Flash Nanodroid

Grab it from here

https://xdaforums.com/apps/magisk/module-nanomod-5-0-20170405-microg-t3584928/amp/
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] dell96kill:
lag

the os very lagger can't run game but l like the features update
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] palmbeach05:
Well excuse us for providing you with the latest android release via derpfest rom. And way to go with bashing the guy who was responsible at breaking through the barriers and getting us on android 10. If he didn't put the time and effort in 8-9 months ago, you would not have been able to enjoy android 10 all this time. Jens is a legend amongst the j5 community. Perhaps if you wanted a gaming phone, you'd get a gaming phone instead of a mid range budget phone from 2015.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] jenslody:
New update uploaded, changelog online (see OP for links).
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] amirizad_7436:
Missed you boss

Thanks:good:
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] ZHIWA-XM:
The lag of launcher has removed or no?

give us feedback, please?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] jenslody:
Launcher is prebuilt lawnchair, so nothing I can do.

And I don't have any significant lags.

You can check this telegram-channel for systemless launchers (magisk needed): https://t.me/shady_mods_releases .

But you will lose any launcher settings when you install it, so saving the settings is a good idea.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] amirizad_7436:
Sir i prefer to guys to use launcher with quick switch magisk module

That's The best way to not lagging on launcher for this device

I was talking to lawnchair devs before and they was talking about that lawnchair lags most of time with shady mods or gapps included lawnchair and this wired ways

Despite i respect shady works but you know when these launcher install as that way doesn't have nicer performance in compare to quick switch

Most of the time it's a better way on this phone even

Also FYI other guys shady will f#$k up your rom's stock launcher and after uninstall it after each reboot all your settings and stuff that you did on your launcher will be lost
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] PhillipJC:
Installed. Working well. Thank you. ;)
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] ZHIWA-XM:
There is a lag in launcher or not?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] FranciscoAlefe:
[MENTION=8340552]jenslody[/MENTION] How to remove system apps from this rom?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] amirizad_7436:
Just Google it

There are also apps that can do it

Btw you need root
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] jenslody:
Magisk + Terminal Debloater module by veez21 is what I use.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] PhillipJC:
I use Nova launcher.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] FranciscoAlefe:
Ok thanks and just for the best rom I've ever used on my j500m

---------- Post added at 01:19 AM ---------- Previous post was at 01:18 AM ----------

Can you tell me a good app for this, but that works on this custom rom?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] Anonymously Famous:
Is there any for galaxy A30?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] amirizad_7436:
Here is j515 thread and not A30!

So no and never would be!

Just search A30 at xda to find roms for your device
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] shaikhnaser:
Dear sir, after a clean install on j53gxx 2nd aim no in call audio sound & phonw app recent list have bug.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] HANNS100:
Great job my friend, that's what we are used to

I still use today your ROM-Pie4j53gxx.4.2-Stable-Shishufied; and to day i installed this rom It is wonderful, although there are some problems

I cannot download from playstore even though there is internet..
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] FranciscoAlefe:
[MENTION=8340552]jenslody[/MENTION] Can you remove the firefox lite browser and replace it with chrome? because firefox lite is very heavy!
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] amirizad_7436:
It's source sided and he won't mess up with source things

Just feel free to remove it dude!

You don't use ios which force to use sth special
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] HANNS100:
what about playstore i can't download anything "Waiting For Download(Download Pending)"
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] amirizad_7436:
Play store's settings-app download preference-ask me every time

This would be helpful always

Any way trying with vpn is more effective
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] FranciscoAlefe:
[MENTION=8340552]jenslody[/MENTION] what is the chance of someone port the ROM of miui 11 to j5 2015?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] amirizad_7436:
Zero percent

If it was open source and then some one was interested in it then it would be possible

Also there is no phone from xiaomi which have sd410 with miui 11 which was possible to port (besides that huge of stuff and hard works)

So no one ui no miui not oos and ......
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] PhillipJC:
Battery life not very good.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] NecromancerViper:
You should see Bliss :rolleyes:
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] PhillipJC:
I have tried Bliss, I think Derpfest is better. Thank you. ??
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] HANNS100:
when installing microG the play store dosn't work there is no app..can some one help me to install microG and activate play store.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] amirizad_7436:
Flash minmicrog standard to make google play work with microg
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] carlos974:
FYI !

Magisk 21.0 : https://github.com/topjohnwu/Magisk/releases/tag/v21.0

MagiskManager 8.0 : https://github.com/topjohnwu/Magisk/releases/tag/manager-v8.0.0
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] FranciscoAlefe:
DELETED
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] carlos974:
Reduce the name of the .jpg files, so that we can see them ;)
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] FranciscoAlefe:
[MENTION=8340552]jenslody[/MENTION] BUG
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] FranciscoAlefe:
[MENTION=8340552]jenslody[/MENTION]
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] palmbeach05:
shouty caps was really needed? The man does have a life you know, you don't need fo yell at him just because he has not replied to you
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] Chingiz232:
Hello [MENTION=8340552]jenslody[/MENTION], can i enable amr-wb codec(hd voice) in voice call on j500h?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] palmbeach05:
Are you done spamming every damn thread known to mankind?

And use the app Night Mode for Samsung. May have to google it, i think it got taken off of play store
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] testquery:
i am not spamming here but trying to get my j5 working without flickering. Tried oled saver, flicker free , but still some flickering is noteciable.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] palmbeach05:
Welcome to having a 5 yr old about to be 6 yr old device bud. Time to repair, replace, or move on
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] testquery:
i think its samsung's implemetation itself that flickering never ends, might be someother company with oled display and dc dimming enabled device to consider.
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] stievy:
Alright, I'm booting the first time (I see the Google logo after the getting apps ready or something), but it takes forever (like over 15 min now)... Is this normal? I'm on j5nlte (DerpFest-10-Community-j5nlte-20200913-VANILLA).

Rebooted, but it's at an hour already now... Is there something I can check?
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] amirizad_7436:
I didn't got it completely

You can't boot into a system?

Or it takes one hour to boot??!!!
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] stievy:
It's stuck on this screen for over an hour now. I just turned it off before you replied.

https://i.imgur.com/JGfL8uI.jpg

---------- Post added at 09:30 PM ---------- Previous post was at 09:08 PM ----------

I wiped system and data and then reloaded the image and now it works :)
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] Gabriel261:
Good work
[Samsung Galaxy J5 (2015) ROMs, Kernels, Recoveries] asliaral:
Hello

İ could remove apps with root and a app like App2sd,Link2sd,Titanium etc.

But İ cant remove on this rom. İt says a mistake.

İs it normal?

İ am on j500f. The first open and the others was fast. But sometimes, lock screen opens late. But sometimes.. Sometimes is fast.

And gallery's settings menu is not working. İt has make me wait on blackscreen.

İ did Turkish system language but firefox lite has no Turkish and it is on system language but English. So İ wanted to remove this too.

Sorry my English.
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] jenslody:
​

Disclaimer

I am not responsible if flashing this ROM bricks your phone or causes thermonuclear war
and ends the world as we know it.
You have been warned.

Rom-Information

​

DerpFest 10 (based on Android 10) Unofficial VANILLA (no gapps)​

​

More information about the rom can be found on the:​

DerpFests website,

DerpFests Telegram

What works

amost evrything you need​

in detail, most stuff works: ril, wifi, gps, video, audio, bt-audio, pip, nfc, drm, fm-radio,​

except what's listed in bugs​

encryption works, decryption in TWRP also (at least with my TWRP), more details come, be careful and take a full backup before encrypting​

​

Bugs

probably dual-sim issues (possible workaround in second post)

no Volte!

You tell me

Credits

​

all Galaxy-MSM8916 devs and contributors for the base trees​

@Zakaryan2004 for some telegram chats about our device​

@SebaUbuntu for fixing nfc and drm​

the DerpFest team for the great rom​

the xda community​

​

Sources

​

manifest from DerpFests main sources

my local_manifests file pulls in several (slightly) modified or otherwise needed repos (e.g.):​

android_hardware_qcom_audio

android_external_sony_boringssl-compat

android_packages_apps_Exchange

android_packages_apps_Email

and my device-tree:​

android_device_samsung_qcom-common

android_device_samsung_j5xnlte

android_device_samsung_msm8916-common

proprietary_vendor_samsung

Downloads from my server

SM-J510x

j5xnlte (rom)

j5xnlte (md5sum)

j5xnlte (full changelog)

j5xnlte (TWRP 3.3.1)

j5xnlte (TWRP 3.3.1 for Odin)

Instructions

​

At least MarshMallow bootloader is required or you will not be able to boot the rom !​

Latest stock firmware is recommended before installing this rom, even if it might work with older versions !​

You have to reboot one time after first boot to make mobile data work.​

Use the TWRP from the download-link for your device above (needs to be flashed from existing TWRP, or use ODIN version)

Download the latest build

Put it on your device

Reboot to TWRP

Take a full backup

If you want to be sure wipe the device

Flash the latest build

Clean Cache and Dalvik if you want

Reboot and enjoy

Others

​

Easily rootable with the great Magisk (stable) by @topjohnwu.​

I use it as daily driver without major issues, except mobile data (see above).​

I use microG as google replacement and for push-services, signature-spoofing is already build into the rom but need to be enabled in "Settings -> DerpQuest -> More" and granted in microG-Settings or "Settings -> Apps & notifications -> Permission manager".​

​

XDA:DevDB Information

DerpFest 10 (Q) for J5 (2016)[SM-J510x][VANILLA][UNOFFICIAL], ROM for the Samsung Galaxy J5

Contributors

jenslody

ROM OS Version: Android 10

ROM Kernel: Linux 3.10.x

ROM Firmware Required: Stock MarshMallow bootloader and modem

Based On: AOSIP

Version Information

Status: Beta

Created 2020-08-15

Last Updated 2020-09-13
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] RootedLee:
mighty cool - danke Jens
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Rajawi04:
Thank you so much Jens for all you do to keep this device alive :)/
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] abdogeni:
I have tested this ROM and il like the look of it because it is almost pixel skin, but i'm wondering why the blissROM is faster then any other Q ROM for this device?
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] RootedLee:
[MENTION=7120892]abdogeni[/MENTION] - do you mean BlissROM boots to your home screen faster, or it's faster running and working with apps, or both? If one or more app(s) lag for you in this DerpFest ROM, which one(s)?
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] abdogeni:
[MENTION=8521435]RootedLee[/MENTION] - ok, it's faster running apps and in transition and more responsive, at first I thought it's the window and transition animation but it isn't, I can't explain the difference but the only name that's cames in my head is the speed. It's like you use a 90Hz screen or something.
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Arbab(AB):
Sir [MENTION=8340552]jenslody[/MENTION] why are you so silent?

Is everything alright?
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] jenslody:
Nothing to say, no new updates at the moment.

Besides this, no still struggling with private stuff, so far from being alright, unfortunately.
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Arbab(AB):
Sir You are alright, that's enough for us❤

Take care...
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Danieke77A:
Dear i'm new with flash rom on samsung ... i used odin to flash twrp but in phone read frp lock and can't flash TWRP

unfortunally i can't enter in my phone i restore screen lcd after my friend broken and now forget pattern to unlock... hot to fix this???
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] jenslody:
New update uploaded, changelog online (see OP for links).
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Jagdishjangu:
Thanks :good:

Waiting for official build
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] RootedLee:
Thank you, Jens.

Stay strong, Kopf hoch!
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] gartner:
Hi and thanks for the ROM. it looks very nice.

I just wonder if it's possebly to remove the firefox lite in some how... ? I whant to use the normal Firefox...

Regards

Gartner
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Akash23q2:
You can use any system app remover application from playstore or download its apk.
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Rajawi04:
It's better to use Batch Uninstaller or Oandbackupx from F-droid
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Bogdans29:
TWRP 3.3.1 link are dead..
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] daywalk3r666:
https://android.jenslody.de/TWRP/j5xnlte/TWRP_3.3.1-0_j5xnlte_20200215_140306_jenslody.img

https://android.jenslody.de/TWRP/j5xnlte/TWRP_3.3.1-0_j5xnlte_20200215_140306_jenslody.tar.md5
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] iamlaybhari:
Take Care Sir. and Thanks for this ROM :)
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Errick27:
Error 404 sir
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] RootedLee:
only https://android.jenslody.de/TWRP/j5xnlte/TWRP_3.3.1-0_j5xnlte_20200215_140903_jenslody.img is down (+ the corresponding .md5 file).

Hey Jens, lass es dir gut gehen & guten Rutsch :)
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Sadman Fahad:
Is it working in j510UN
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] jenslody:
I don't know how this could happen, but the link is fixed in OP.

Thanks for reporting.

Danke für die guten Wünsche, Dir auch alles Gute.
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Skorpion9:
Hey there!

Dual-sim is workig, encription is working, so now I am happy with this rom, thanks! (for some unknown reasons I had no success with encryption in other roms, that's why my happiness)

I have one more thing, which is annoying, that is battery usage with a sim card. I have 2 sim cards from different providers and only happens with one of them, no matter which slot I use. Only that card causes drainage, if I just use the other, it will go normal (normal battery life with effective deep sleep). But everything is working well, callings, data, mms, so strange. So I think either the sim is wrong, or the modem should be updated. It happened with all the roms I've tried. Do you know where can I find flashable modem drivers for my area/provider? Or do you know if I can extract the modem from a stock firmware zip, than flash it on Derpfest?

Any help or experience is appreciated.

Happy new year, btw!
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] jenslody:
The modem itself is not touched by the rom and the blobs used in device-tree are from stock.

So the modem-version depends on your last stock-version you had on your device..

If one sim goes crazy, it can be because of a bad signal or too much towers seen by the sim "hopping" around, which causes a heavy drain.

I have been at one place (at work) where my device went from 100% to zero in less than 8 hours, but was stable if I had no connection at all.

SatStat showed about 5 to ten (I don't remember exactly) towers with low signal amd the device could not decide which one to use.
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Skorpion9:
Ok, I see, thanks for the insight. I will start using that SatStat app, let's see what is it saying. But the battery draining is pretty constant wherever I go in the country, in work or at home.

I've seen on sammobile, that an updated firmware is available for my provider from 2020 dec.21. Is it worth trying to flash it and reinstall derpfest afterwards, or I am talking nonsense?
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Skorpion9:
Latest Samsung Galaxy J5 2016 firmware

Download the latest Samsung firmware for Galaxy J5 2016 with model code SM-J510F. Check out our free download or super fast premium options.

www.sammobile.com
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] jenslody:
You can at least give it a try.

You can take a full backup with TWRP and restore system, data, cache and boot after updating stock.

To save your media, you can either use @ianmacd's magisk module (never tried it myself) or copy /data/media to /data/local/tmp before saving and copy it back after restore (and delete it below /data/local/tmp after restore).
[Samsung Galaxy J5 (2016) ROMs, Kernels, Recoveries] Skorpion9:
Okay, I will report. Thanks for your help!