Nada, que no lo consigo, copio y pego quitando únicamente parte de la numeración que me dieron en la tienda de páginas amarillas...

Si, si, la tarjeta es Evo Plus, roja y blanca que venía en su embalaje original comprada en Amazon, la del enlace que puse antes, que es de Filipinas tal y como ponías en el post original.

He visto mil videos y leído todo lo que ha caído en mis manos y no consigo dar con ello...

root@ubuntu:/usr/local/src# cd evoplus_cid/jni
root@ubuntu:/usr/local/src/evoplus_cid/jni# gcc evoplus_cid.c -o evoplus_cid
evoplus_cid.c: In function ‘parse_serial’:
evoplus_cid.c:107:7: warning: implicit declaration of function ‘strlen’ [-Wimplicit-function-declaration]
if ((strlen(str) > 2) && (str[0] == '0') &&
^
evoplus_cid.c:107:7: warning: incompatible implicit declaration of built-in function ‘strlen’
evoplus_cid.c:107:7: note: include ‘<string.h>’ or provide a declaration of ‘strlen’
evoplus_cid.c:109:9: warning: implicit declaration of function ‘strtol’ [-Wimplicit-function-declaration]
val = strtol(str, NULL, 16);
^
evoplus_cid.c: In function ‘main’:
evoplus_cid.c:135:8: warning: incompatible implicit declaration of built-in function ‘strlen’
len = strlen(argv[2]);
^
evoplus_cid.c:135:8: note: include ‘<string.h>’ or provide a declaration of ‘strlen’
evoplus_cid.c:179:2: warning: implicit declaration of function ‘close’ [-Wimplicit-function-declaration]
close(fd);
^
root@ubuntu:/usr/local/src/evoplus_cid/jni# ll
total 36
drwxr-xr-x 2 root root 160 Jan 30 10:47 ./
drwxr-xr-x 5 root root 160 Jan 30 10:38 ../
-rw-r--r-- 1 root root 287 Jan 30 10:38 Android.mk
-rwxr-xr-x 1 root root 13456 Jan 30 10:47 evoplus_cid*
-rw-r--r-- 1 root root 3927 Jan 30 10:38 evoplus_cid.c
-rw-r--r-- 1 root root 950 Jan 30 10:38 ioctl.h
-rw-r--r-- 1 root root 3979 Jan 30 10:38 major.h
-rw-r--r-- 1 root root 1729 Jan 30 10:38 mmc.h
root@ubuntu:/usr/local/src/evoplus_cid/jni# ./evoplus_cid
Usage: ./evoplus_cid <device> <cid> [serial]
device - sd card block device e.g. /dev/block/mmcblk1
cid - new cid, must be in hex (without 0x prefix)
it can be 32 chars with checksum or 30 chars without, it will
be updated with new serial number if supplied, the checksum is
(re)calculated if not supplied or new serial applied
serial - optional, can be hex (0x prefixed) or decimal
and will be applied to the supplied cid before writing

Warning: use at own risk!
root@ubuntu:/usr/local/src/evoplus_cid/jni# find /sys -name cid -print
/sys/devices/pci0000:00/0000:00:1c.1/0000:04:00.1/mmc_host/mmc0/mmc0:0001/cid
root@ubuntu:/usr/local/src/evoplus_cid/jni# more /sys/devices/pci0000:00/0000:00:1c.1/0000:04:00.1/mmc_host/mmc0/mmc0:0001/cid
1b534d454231515430a4db5f58011c00
root@ubuntu:/usr/local/src/evoplus_cid/jni# ./evoplus_cid /dev/mmcblk0 094150xxxxxxxxxxxxxx57011900
Failed to enter vendor mode. Genuine Samsung Evo Plus?
root@ubuntu:/usr/local/src/evoplus_cid/jni#