Comment 4 for bug 1764008

Same trouble with Initial RC image 20180421.1
Installing on ThinkPad X41 with two drives. Seemed to install, on reboot got black screen with blinking cursor top left.

System is:
kubuntu@kubuntu:~$ inxi -Fxz
System: Host: kubuntu Kernel: 4.15.0-15-generic i686 bits: 32 gcc: 7.3.0 Console: tty 3
           Distro: Ubuntu Bionic Beaver (development branch)
Machine: Device: laptop System: IBM product: 2526C3U v: ThinkPad X41 serial: <filter>
           Mobo: IBM model: 2526C3U serial: <filter> BIOS: IBM v: 74ET64WW (2.09 ) date: 12/14/2006
Battery BAT0: charge: 41.4 Wh 96.8% condition: 42.8/44.0 Wh (97%) model: SANYO IBM-92P1003 status: N/A
CPU: Single core Intel Pentium M (-UP-) arch: Dothan rev.8 cache: 2048 KB
           flags: (nx pae sse sse2) bmips: 3192 speed: 1600 MHz (max)
Graphics: Card: Intel Mobile 915GM/GMS/910GML Express Graphics Controller bus-ID: 00:02.0
           Display Server: X.Org 1.19.6 drivers: intel (unloaded: modesetting,fbdev,vesa)
           Resolution: 1024x768@50.00hz
           OpenGL: renderer: Mesa DRI Intel 915GM x86/MMX/SSE2 version: 1.4 Mesa 18.0.0-rc5 Direct Render: Yes
Audio: Card Intel 82801FB/FBM/FR/FW/FRW (ICH6 Family) AC'97 Audio Controller
           driver: snd_intel8x0 ports: 1c00 18c0 bus-ID: 00:1e.2
           Sound: Advanced Linux Sound Architecture v: k4.15.0-15-generic
Network: Card-1: Broadcom Limited NetXtreme BCM5751M Gigabit Ethernet PCI Express
           driver: tg3 v: 3.137 bus-ID: 02:00.0
           IF: enp2s0 state: down mac: <filter>
           Card-2: Intel PRO/Wireless 2200BG [Calexico2] Network Connection
           driver: ipw2200 v: 1.2.2kmprq bus-ID: 04:02.0
           IF: wlp4s2 state: up mac: <filter>
Drives: HDD Total Size: 141.9GB (2.5% used)
           ID-1: /dev/sda model: SAMSUNG_MZMPA064 size: 64.0GB temp: 0C
           ID-2: /dev/sdb model: HTS541060G9SA00 size: 60.0GB temp: 38C
           ID-3: USB /dev/sdc model: DataTraveler_2.0 size: 2.0GB temp: 0C
           ID-4: USB /dev/sdd model: USB_2.0_FD size: 15.8GB temp: 0C
Partition: ID-1: / size: 1002M used: 205M (21%) fs: overlay dev: N/A
RAID: No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors: System Temperatures: cpu: 54.0C mobo: 47.0C
           Fan Speeds (in rpm): cpu: 4677
Info: Processes: 162 Uptime: 31 min Memory: 571.6/2003.0MB Init: systemd runlevel: 5 Gcc sys: N/A
           Client: Shell (sudo) inxi: 2.3.56
kubuntu@kubuntu:~$

At start of installation, both drives were empty FAT32. After installation sdb was in the logical volume but still FAT32. sdb is in a bay in the docking station for the laptop.