Check your log with dmesg to see if the out of memory killer operated. The warning messages you saw before the crash are normal because this hardware does not have a second PS/2 port for use with the mouse logic. Vivado is pretty memory hungry but 8Gbytes (twice what you have) should be sufficient. The build was tested with 16Gbytes and it is preferable to use SSD disk. You can also add swap space to your existing configuration but runtime will probably be disappointing. Sent from my iPhone > On 26 Dec 2018, at 10:14, Dinesh Thirumurthy < dinesh.thirumurthy(a)gmail.com&gt; wrote: > > Hi, > > While doing > > make bitstream > > as given in > > https://www.lowrisc.org/docs/generate-the-bitstream/ > > I get the following error: > > --------------------------------------------------------------------------------- > Start Area Optimization > --------------------------------------------------------------------------------- > WARNING: [Synth 8-3332] Sequential element (IOBUF_inst) is unused and will > be removed from module io_buffer_generic__3. > WARNING: [Synth 8-3332] Sequential element (IOBUF_inst) is unused and will > be removed from module io_buffer_generic. > WARNING: [Synth 8-3332] Sequential element (timer_5usec_count_reg[7]) is > unused and will be removed from module ps2_keyboard. > WARNING: [Synth 8-3332] Sequential element (timer_5usec_count_reg[6]) is > unused and will be removed from module ps2_keyboard. > WARNING: [Synth 8-3332] Sequential element (timer_5usec_count_reg[5]) is > unused and will be removed from module ps2_keyboard. > WARNING: [Synth 8-3332] Sequential element (timer_5usec_count_reg[4]) is > unused and will be removed from module ps2_keyboard. > WARNING: [Synth 8-3332] Sequential element (timer_5usec_count_reg[3]) is > unused and will be removed from module ps2_keyboard. > WARNING: [Synth 8-3332] Sequential element (timer_5usec_count_reg[2]) is > unused and will be removed from module ps2_keyboard. > WARNING: [Synth 8-3332] Sequential element (timer_5usec_count_reg[1]) is > unused and will be removed from module ps2_keyboard. > WARNING: [Synth 8-3332] Sequential element (timer_5usec_count_reg[0]) is > unused and will be removed from module ps2_keyboard. > /home/rise/tools/Vivado/Vivado/2016.1/bin/loader: line 164: 6678 > Killed "$RDI_PROG" "$@" > Parent process (pid 6678) has died. This helper process will now exit > [Wed Dec 26 15:27:09 2018] synth_1 finished > wait_on_run: Time (s): cpu = 00:04:14 ; elapsed = 00:09:40 . Memory (MB): > peak = 1161.652 ; gain = 3.898 ; free physical = 2757 ; free virtual = 3474 > # launch_runs impl_1 -to_step write_bitstream > ERROR: [Common 17-70] Application Exception: Failed to launch run 'impl_1' > due to failures in the following run(s): > synth_1 > These failed run(s) need to be reset prior to launching 'impl_1' again. > > INFO: [Common 17-206] Exiting Vivado at Wed Dec 26 15:27:25 2018... > Makefile:151: recipe for target > 'lowrisc-chip-imp/lowrisc-chip-imp.runs/impl_1/chip_top.bit' failed > make: *** [lowrisc-chip-imp/lowrisc-chip-imp.runs/impl_1/chip_top.bit] > Error 1 > dt@m:~/l/lowrisc-chip/fpga/board/nexys4_ddr$ > > I am using an 4GB RAM Ubuntu 16.04.5 > > dt@marina:~/l/e/nexys$ lsb_release -a; cat /proc/meminfo | head > No LSB modules are available. > Distributor ID: Ubuntu > Description: Ubuntu 16.04.5 LTS > Release: 16.04 > Codename: xenial > MemTotal: 3733908 kB > MemFree: 1683560 kB > MemAvailable: 2417840 kB > Buffers: 23752 kB > Cached: 1087320 kB > SwapCached: 17312 kB > Active: 963596 kB > Inactive: 903124 kB > Active(anon): 749428 kB > Inactive(anon): 201432 kB > > Any suggestions on how to overcome this? > > This is refresh-v0.6 > > Thanks. > > Regards, > Dinesh