The series of non-printable-ASCII characters followed by "ftmtoolerror" is exactly what Compal's bootloader emits on boot (the non-printable- ASCII characters constitute PROMPT1 for a possible external code download), so the fact that you are seeing these characters with your cu terminal proves that your phone is good (has an unlocked bootloader) and that your serial cable is good at least in the phone to PC direction. It is possible that your cable may be broken in the PC to phone direction, or that the headset jack connection inside the phone itself is broken in that direction - I have seen such broken headset jack connections on some busted-up phones. However, this other part of your report raises other concerns: Are you saying that absolutelyno messages whatsoever appear in the console window where you run osmocon as you press thr power button on the phone? If so, then you must have some other problem, as osmocon should at least report that it got PROMPT1 from the phone, even if it is not successful in talking back to the phone. M~

I tried to execute the osmocon command (sudo ./osmocon -p /dev/tty/USB0) using strace. The output is as follows: ====== strace output starts======== execve("./osmocon", ["./osmocon", "-p", "/dev/tty/USB0"], [/* 74 vars */]) = 0 brk(NULL) = 0x1b7c000 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=164422, ...}) = 0 mmap(NULL, 164422, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fb924694000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/x86_64-linux-gnu/libtalloc.so.2", O_RDONLY|O_CLOEXEC) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\340\35\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=80144, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb924693000 mmap(NULL, 2175248, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb924284000 mprotect(0x7fb924297000, 2093056, PROT_NONE) = 0 mmap(0x7fb924496000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x12000) = 0x7fb924496000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/local/lib/libosmocore.so.11", O_RDONLY|O_CLOEXEC) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0 \230\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=710920, ...}) = 0 mmap(NULL, 2264912, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb92405b000 mprotect(0x7fb924080000, 2097152, PROT_NONE) = 0 mmap(0x7fb924280000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x25000) = 0x7fb924280000 mmap(0x7fb924282000, 8016, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fb924282000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\t\2\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0 mmap(NULL, 3971488, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb923c91000 mprotect(0x7fb923e51000, 2097152, PROT_NONE) = 0 mmap(0x7fb924051000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1c0000) = 0x7fb924051000 mmap(0x7fb924057000, 14752, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fb924057000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/x86_64-linux-gnu/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\240\r\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=14608, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb924692000 mmap(NULL, 2109680, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb923a8d000 mprotect(0x7fb923a90000, 2093056, PROT_NONE) = 0 mmap(0x7fb923c8f000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7fb923c8f000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb924691000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb924690000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb92468f000 arch_prctl(ARCH_SET_FS, 0x7fb924690700) = 0 mprotect(0x7fb924051000, 16384, PROT_READ) = 0 mprotect(0x7fb923c8f000, 4096, PROT_READ) = 0 mprotect(0x7fb924496000, 4096, PROT_READ) = 0 mprotect(0x7fb924280000, 4096, PROT_READ) = 0 mprotect(0x605000, 4096, PROT_READ) = 0 mprotect(0x7fb9246bd000, 4096, PROT_READ) = 0 munmap(0x7fb924694000, 164422) = 0 rt_sigaction(SIGPIPE, {SIG_IGN, [PIPE], SA_RESTORER|SA_RESTART, 0x7fb923cc64b0}, {SIG_DFL, [], 0}, 8) = 0 rt_sigaction(SIGALRM, {SIG_IGN, [ALRM], SA_RESTORER|SA_RESTART, 0x7fb923cc64b0}, {SIG_DFL, [], 0}, 8) = 0 rt_sigaction(SIGHUP, {0x7fb924070800, [HUP], SA_RESTORER|SA_RESTART, 0x7fb923cc64b0}, {SIG_DFL, [], 0}, 8) = 0 rt_sigaction(SIGIO, {SIG_IGN, [IO], SA_RESTORER|SA_RESTART, 0x7fb923cc64b0}, {SIG_DFL, [], 0}, 8) = 0 open("/dev/tty/USB0", O_RDWR|O_NOCTTY|O_NONBLOCK|O_SYNC) = -1 ENOTDIR (Not a directory) write(2, "Cannot open serial device /dev/t"..., 40) = 40 exit_group(1) = ? +++ exited with 1 +++ ====== strace output ends======== The output of $ sudo stty -F /dev/ttyUSB0 is === stty output starts=== speed 115200 baud; line = 0; -brkint -imaxbel === stty output ends=== Whereas setserial command (sudo setserial -a /dev/ttyUSB0) gives this error: Cannot get serial info: Inappropriate ioctl for device What can be wrong with my PC to phone communication ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ On Friday, December 28, 2018 10:19 AM, haiderali91 haiderali91(a)protonmail.com wrote: > Thanks Mychaela for replying in detail. > Yes, there is no response on executing the whole command: > $ sudo ./osmocon -p /dev/ttyUSB0 -m c123xor ../../target/firmware/board/compal_e88/hello_world.compalram.bin > However, when i execute the following: > $sudo ./osmocon -p /dev/ttyUSB0 > It returns: Cannot open serial device /dev/tty/USB0 > Trying to figure out the problem.. > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > On Wednesday, December 26, 2018 9:16 PM, Mychaela Falconia mychaela.falconia(a)gmail.com wrote: > > > > I have also attached a cu terminal by using following command. > > > $ sudo cu -l /dev/ttyUSB0 -s 115200 > > > The cu terminal displays this message on pressing power button. > > > [garbage characters]ftmtoolerror > > > > The series of non-printable-ASCII characters followed by "ftmtoolerror" > > is exactly what Compal's bootloader emits on boot (the non-printable- > > ASCII characters constitute PROMPT1 for a possible external code > > download), so the fact that you are seeing these characters with your > > cu terminal proves that your phone is good (has an unlocked bootloader) > > and that your serial cable is good at least in the phone to PC > > direction. It is possible that your cable may be broken in the PC to > > phone direction, or that the headset jack connection inside the phone > > itself is broken in that direction - I have seen such broken headset > > jack connections on some busted-up phones. However, this other part > > of your report raises other concerns: > > > > > sudo ./osmocon -p /dev/ttyUSB0 -m c123xor ../../target/firmware/board/compal_e88/hello_world.compalram.bin > > > But I am not getting any response on pressing power button briefly. > > > The command keeps on executing without any message. > > > > Are you saying that absolutelyno messages whatsoever appear in the > > console window where you run osmocon as you press thr power button on > > the phone? If so, then you must have some other problem, as osmocon > > should at least report that it got PROMPT1 from the phone, even if it > > is not successful in talking back to the phone. > > M~