pfSense

Problem:
While installing version 2.4.2 via USB key onto a Wyse D50D or D90D, the video is corrupt from the bootloader and into the installation wizard.

Description:
Characters are unreadable in text-mode.
I am able to see the bootloader.
I am unable to see text in the install wizard.
Photos attached.
Installation source was file: "pfSense-CE-memstick-2.4.2-RELEASE-amd64.img.gz"
The effect is that a recovery from a config.xml which was created in 2.4.x cannot be carried out as the installation wizard is not accessible.

This same defect is documented here with a workaround, but was not observed by me during my initial troubleshooting.
https://forum.pfsense.org/index.php?topic=139592.0

Troubleshooting:

Tested on three monitors:
- Dell 19" LCD,
- HP 17" LCD
- Samsung TV.
The nature of the corruption was the same in all cases.

Tested using the DVI port on the Wyse in addition to the DisplayPort output. The nature of the corruption was the same in all cases.

Tested multiple versions of pfSense:
- pfSense 2.3.5 - No problem encountered.
- pfSense 2.4.1 - Display corruption encountered
- pfSense 2.4.2 - Display corruption encountered

Tested multiple clients:
- Wyse D50D - Display corruption encountered
- Wyse D90D - Display corruption encountered
- Wyse 7040 with Intel HD 530 on HDMI - No problem encountered.

Tested multiple workarounds:

1. Ref: https://forum.pfsense.org/index.php?topic=126859.0
From the installation media, edit /boot/device.hints and added:
- hint.sc.0.flags="0x180"
- hint.sc.0.vesa_mode="279"
The installer hung while entering text mode.

2. Ref: https://forum.pfsense.org/index.php?topic=140702.0
From the installation media, edit /boot/loader.conf and added:
- hw.vga.textmode=0
- kern.vt.fb.default_mode="1024x768"
The installer hung while entering text mode.

3.
From the kernel command line at boot-time:
Added the statements:
- hw.vga.textmode=0
- kern.vt.fb.default_mode="1024x768"
- boot

Configuration:

pciconf -lv:
vgapci0@pci0:0:1:0: class=0x030000 card=0x98041002 chip=0x98041002 rev=0x00 hdr=0x00
vendor = 'Advanced Micro Devices, Inc. [AMD/ATI]'
device = 'Wrestler [Radeon HD 6250]'
class = display
subclass = VGA

Workaround:

Install 2.3.5, upgrade to next major release via the menu or GUI. Then import the config.xml from the GUI.