I've been trying to port the a7y17lte for a while now. But I encountered a lot of issue with the kernel compilation. There were a couple implicit declaration warning that caused errors because of the build options. Fortunately, I was able to fix those. But I then encountered other strange errors.

/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/net/ipv6/syncookies.c: In function 'cookie_v6_check':
/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/net/ipv6/syncookies.c:186:4: error: 'mopt' undeclared (first use in this function)
   &mopt, 
    ^
/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/net/ipv6/syncookies.c:186:4: note: each undeclared identifier is reported only once for each function it appears in
  CC      lib/string.o
make[3]: *** [/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/scripts/Makefile.build:279: net/ipv6/syncookies.o] Error 1
make[2]: *** [/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/scripts/Makefile.build:486: net/ipv6] Error 2

and

In file included from /home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/include/uapi/linux/posix_types.h:4:0,
                 from /home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/include/uapi/linux/types.h:13,
                 from /home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/include/linux/compiler.h:214,
                 from /home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/include/linux/linkage.h:4,
                 from /home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/include/linux/kernel.h:6,
                 from /home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/include/linux/skbuff.h:26,
                 from /home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/include/linux/tcp.h:21,
                 from /home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/net/ipv4/syncookies.c:13:
/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/net/ipv4/syncookies.c: In function 'cookie_v4_check':
/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/include/linux/stddef.h:7:14: error: passing argument 4 of 'tcp_parse_options' makes integer from pointer without a cast [-Werror]
 #define NULL ((void *)0)
              ^
/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/net/ipv4/syncookies.c:292:38: note: in expansion of macro 'NULL'
  tcp_parse_options(skb, &tcp_opt, 0, NULL);
                                      ^
In file included from /home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/include/net/mptcp.h:46:0,
                 from /home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/net/ipv4/syncookies.c:20:
/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/include/net/tcp.h:591:6: note: expected 'int' but argument is of type 'void *'
 void tcp_parse_options(const struct sk_buff *skb,
      ^
/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/net/ipv4/syncookies.c:292:2: error: too few arguments to function 'tcp_parse_options'
  tcp_parse_options(skb, &tcp_opt, 0, NULL);
  ^
In file included from /home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/include/net/mptcp.h:46:0,
                 from /home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/net/ipv4/syncookies.c:20:
/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/include/net/tcp.h:591:6: note: declared here
 void tcp_parse_options(const struct sk_buff *skb,
      ^
cc1: all warnings being treated as errors
make[3]: *** [/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/scripts/Makefile.build:279: net/ipv4/syncookies.o] Error 1
make[3]: *** Waiting for unfinished jobs....
  CC      drivers/hwmon/sec_thermistor.o
make[2]: *** [/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/scripts/Makefile.build:486: net/ipv4] Error 2
make[1]: *** [/home/arashk/Projects/Ubuntu-touch/non-standalone/halium/kernel/samsung/universal7880/Makefile:1046: net] Error 2

A note regarding the &mopt error. I can't just remove those lines of code since they run when a config is set in the kernel config file. And that config is most certainly set.
Another thing to note is that I'm using archlinux. Therefore I'm using gcc 11 to compile this. I also have gcc 9 installed (from the AUR) but setting the CC flag to gcc-9 didn't seem to do anything other than some outputs saying the CC flag is already set. If I'm doing something wrong, please tell me. I also saw that while running "mka mkbootimg" it said:
libmediaplayerservice/Android.mk: no such file or directory
It compiled fine but I checked and that framework contained the older android.bp format.

@tabimon It all depends on the hardware. Use the lineage sources, the lineage device info pages, and the ubports gitlab to find that out. I found out that the a5y17lte is the exact same as a7y17lte in terms of requirements for a bootable image.

@flohack I see... then it's not a complete necessity, thank you very much.

@flohack Thank you for the reply. I honestly would start from halium 9. But I remember reading somewhere in the docs that the installed version of android needs to be the same as the halium version being built on. Can I get some context for this statement? Maybe I read it on a part unrelated to porting ubuntu touch or something.

Hello, I started the port of a7y17lte (Samsung galaxy A7 2017) using the halium 11 kernel. (The latest android version provided by samsung is 8 and NOT 8.1. Therefore I'm using lineage os 18.1 which uses android 11) I noticed that the halium-boot repo doesn't have a halium-11 branch. Only master and halium 9. It's also not in the repo file. What should I do for the kernel config file, since it needs to be changed?

Hello, I've been trying to port my device (Samsung a7y17lte). But when I was reading the documentation, I noticed that there were notes of halium version 7.1, 9 and 10. But the build process was only available for 7.1 and 9. I assume the build process would be the same for 10. But the fact that it doesn't say "9 and up" is a bit worrisome. I wanted to know what versions of halium are currently usable with UBports? Because I also saw no mentions of halium 11.