g4ad.x16xlarge Ubuntu 18.04 GPU driver issue

I've installed the gpu driver, mate desktop and nice-dcv following the official guide: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/install-amd-driver.html

Everything works fine for g4ad.xlarge ... g4ad.8xlarge. But when I change instance type to g4ad.16xlarge, Xorg won't start. My first guess was that it's related to multiple GPUs, but 8xlarge already has 2 of them and it works just fine. Here's the Xorg log:

[    20.536] (==) Log file: "/var/log/Xorg.0.log", Time: Sat Jan 22 05:35:22 2022
[    20.536] (==) Using config file: "/etc/X11/xorg.conf"
[    20.536] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[    20.537] (==) ServerLayout "Layout0"
[    20.537] (**) |-->Screen "Screen0" (0)
[    20.537] (**) |   |-->Monitor "Monitor0"
[    20.537] (**) |   |-->Device "Device0"
[    20.537] (**) |-->Input Device "Keyboard0"
[    20.537] (**) |-->Input Device "Mouse0"
[    20.537] (==) Automatically adding devices
[    20.537] (==) Automatically enabling devices
[    20.537] (==) Automatically adding GPU devices
[    20.537] (==) Automatically binding GPU devices
[    20.537] (==) Max clients allowed: 256, resource mask: 0x1fffff
[    20.537] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
[    20.537]    Entry deleted from font path.
[    20.537] (WW) The directory "/usr/share/fonts/X11/100dpi/" does not exist.
[    20.537]    Entry deleted from font path.
[    20.537] (WW) The directory "/usr/share/fonts/X11/75dpi/" does not exist.
[    20.537]    Entry deleted from font path.
[    20.537] (WW) The directory "/usr/share/fonts/X11/100dpi" does not exist.
[    20.537]    Entry deleted from font path.
[    20.537] (WW) The directory "/usr/share/fonts/X11/75dpi" does not exist.
[    20.537]    Entry deleted from font path.
[    20.537] (==) FontPath set to:
    /usr/share/fonts/X11/misc,
    /usr/share/fonts/X11/Type1,
    built-ins
[    20.537] (**) ModulePath set to "/opt/amdgpu/lib64/xorg/modules/drivers,/opt/amdgpu/lib/xorg/modules,/opt/amdgpu-pro/lib/xorg/modules/extensions,/opt/amdgpu-pro/lib64/xorg/modules/extensions,/usr/lib64/xorg/modules,/usr/lib/xorg/modules"
[    20.537] (**) Extension "DPMS" is disabled
[    20.537] (WW) Hotplugging is on, devices using drivers 'kbd', 'mouse' or 'vmmouse' will be disabled.
[    20.537] (WW) Disabling Keyboard0
[    20.537] (WW) Disabling Mouse0
[    20.537] (II) Loader magic: 0x55a22090c020
[    20.537] (II) Module ABI versions:
[    20.537]    X.Org ANSI C Emulation: 0.4
[    20.537]    X.Org Video Driver: 23.0
[    20.537]    X.Org XInput driver : 24.1
[    20.537]    X.Org Server Extension : 10.0
[    20.537] (++) using VT number 7

[    20.537] (II) systemd-logind: logind integration requires -keeptty and -keeptty was not provided, disabling logind integration
[    20.538] (II) xfree86: Adding drm device (/dev/dri/card0)
[    20.538] (II) xfree86: Adding drm device (/dev/dri/card1)
[    20.539] (II) xfree86: Adding drm device (/dev/dri/card2)
[    20.540] (II) xfree86: Adding drm device (/dev/dri/card3)
[    20.549] (--) PCI:*(0:0:3:0) 1d0f:1111:0000:0000 rev 0, Mem @ 0xfe000000/4194304, BIOS @ 0x????????/131072
[    20.549] (--) PCI: (0:0:26:0) 1002:7362:1002:0a34 rev 195, Mem @ 0x4040000000/268435456, 0x4080000000/2097152, 0xfe980000/524288
[    20.549] (--) PCI: (0:0:27:0) 1002:7362:1002:0a34 rev 195, Mem @ 0x4050000000/268435456, 0x4080200000/2097152, 0xfea00000/524288
[    20.549] (--) PCI: (0:0:28:0) 1002:7362:1002:0a34 rev 195, Mem @ 0x4060000000/268435456, 0x4080400000/2097152, 0xfea80000/524288
[    20.549] (--) PCI: (0:0:29:0) 1002:7362:1002:0a34 rev 195, Mem @ 0x4070000000/268435456, 0x4080600000/2097152, 0xfeb00000/524288
[    20.549] (II) LoadModule: "glx"
[    20.549] (II) Loading /opt/amdgpu-pro/lib/xorg/modules/extensions/libglx.so
[    20.549] (II) Module glx: vendor="X.Org Foundation"
[    20.549]    compiled for 1.19.0, module version = 1.0.0
[    20.549]    ABI class: X.Org Server Extension, version 10.0
[    20.549] (II) LoadModule: "amdgpu"
[    20.549] (II) Loading /opt/amdgpu/lib/xorg/modules/drivers/amdgpu_drv.so
[    20.550] (II) Module amdgpu: vendor="X.Org Foundation"
[    20.550]    compiled for 1.19.6, module version = 19.1.0
[    20.550]    Module class: X.Org Video Driver
[    20.550]    ABI class: X.Org Video Driver, version 23.0
[    20.550] (II) AMDGPU: Driver for AMD Radeon:
    All GPUs supported by the amdgpu kernel driver
[    20.550] (II) AMDGPU(G0): [KMS] Kernel modesetting enabled.
[    20.551] (II) AMDGPU(G1): [KMS] Kernel modesetting enabled.
[    20.552] (II) AMDGPU(G2): [KMS] Kernel modesetting enabled.
[    20.554] (II) AMDGPU(G3): [KMS] Kernel modesetting enabled.
[    20.556] (EE) No devices detected.
[    20.556] (II) Applying OutputClass "AMDgpu" to /dev/dri/card0
[    20.556]    loading driver: amdgpu
[    20.556] (II) Applying OutputClass "AMDgpu" to /dev/dri/card0
[    20.556]    loading driver: amdgpu
[    20.556] (II) Applying OutputClass "AMDgpu" to /dev/dri/card1
[    20.556]    loading driver: amdgpu
[    20.556] (II) Applying OutputClass "AMDgpu" to /dev/dri/card1
[    20.556]    loading driver: amdgpu
[    20.556] (II) Applying OutputClass "AMDgpu" to /dev/dri/card2
[    20.556]    loading driver: amdgpu
[    20.556] (II) Applying OutputClass "AMDgpu" to /dev/dri/card2
[    20.556]    loading driver: amdgpu
[    20.556] (II) Applying OutputClass "AMDgpu" to /dev/dri/card3
[    20.556]    loading driver: amdgpu
[    20.556] (II) Applying OutputClass "AMDgpu" to /dev/dri/card3
[    20.556]    loading driver: amdgpu
[    20.556] (==) Matched amdgpu as autoconfigured driver 0
[    20.556] (==) Matched amdgpu as autoconfigured driver 1
[    20.556] (==) Matched ati as autoconfigured driver 2
[    20.556] (==) Matched amdgpu as autoconfigured driver 3
[    20.556] (==) Matched amdgpu as autoconfigured driver 4
[    20.556] (==) Matched ati as autoconfigured driver 5
[    20.556] (==) Matched amdgpu as autoconfigured driver 6
[    20.556] (==) Matched amdgpu as autoconfigured driver 7
[    20.556] (==) Matched ati as autoconfigured driver 8
[    20.556] (==) Matched amdgpu as autoconfigured driver 9
[    20.556] (==) Matched amdgpu as autoconfigured driver 10
[    20.556] (==) Matched ati as autoconfigured driver 11
[    20.556] (==) Matched modesetting as autoconfigured driver 12
[    20.556] (==) Matched fbdev as autoconfigured driver 13
[    20.556] (==) Matched vesa as autoconfigured driver 14
[    20.556] (==) Assigned the driver to the xf86ConfigLayout
[    20.556] (II) LoadModule: "amdgpu"
[    20.556] (II) Loading /opt/amdgpu/lib/xorg/modules/drivers/amdgpu_drv.so
[    20.556] (II) Module amdgpu: vendor="X.Org Foundation"
[    20.556]    compiled for 1.19.6, module version = 19.1.0
[    20.556]    Module class: X.Org Video Driver
[    20.556]    ABI class: X.Org Video Driver, version 23.0
[    20.556] (II) LoadModule: "ati"
[    20.556] (II) Loading /usr/lib/xorg/modules/drivers/ati_drv.so
[    20.556] (II) Module ati: vendor="X.Org Foundation"
[    20.556]    compiled for 1.19.6, module version = 18.0.1
[    20.556]    Module class: X.Org Video Driver
[    20.556]    ABI class: X.Org Video Driver, version 23.0
[    20.556] (II) LoadModule: "modesetting"
[    20.556] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so
[    20.556] (II) Module modesetting: vendor="X.Org Foundation"
[    20.556]    compiled for 1.19.6, module version = 1.19.6
[    20.556]    Module class: X.Org Video Driver
[    20.556]    ABI class: X.Org Video Driver, version 23.0
[    20.556] (II) LoadModule: "fbdev"
[    20.556] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so
[    20.556] (II) Module fbdev: vendor="X.Org Foundation"
[    20.556]    compiled for 1.19.3, module version = 0.4.4
[    20.556]    Module class: X.Org Video Driver
[    20.556]    ABI class: X.Org Video Driver, version 23.0
[    20.556] (II) LoadModule: "vesa"
[    20.556] (II) Loading /usr/lib/xorg/modules/drivers/vesa_drv.so
[    20.556] (II) Module vesa: vendor="X.Org Foundation"
[    20.556]    compiled for 1.19.3, module version = 2.3.4
[    20.556]    Module class: X.Org Video Driver
[    20.556]    ABI class: X.Org Video Driver, version 23.0
[    20.556] (II) AMDGPU: Driver for AMD Radeon:
    All GPUs supported by the amdgpu kernel driver
[    20.556] (II) modesetting: Driver for Modesetting Kernel Drivers: kms
[    20.556] (II) FBDEV: driver for framebuffer: fbdev
[    20.556] (II) VESA: driver for VESA chipsets: vesa
[    20.556] (WW) xf86OpenConsole: setpgid failed: Operation not permitted
[    20.556] (WW) xf86OpenConsole: setsid failed: Operation not permitted
[    20.556] (WW) Falling back to old probe method for modesetting
[    20.556] (WW) Falling back to old probe method for fbdev
[    20.556] (WW) Falling back to old probe method for vesa
[    20.556] (WW) Falling back to old probe method for modesetting
[    20.556] (WW) Falling back to old probe method for fbdev
[    20.556] (WW) Falling back to old probe method for vesa
[    20.556] (EE) No devices detected.
[    20.557] (EE)
Fatal server error:
[    20.557] (EE) no screens found(EE)
[    20.557] (EE)
Please consult the The X.Org Foundation support
     at http://wiki.x.org
 for help.
[    20.557] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[    20.557] (EE)
[    20.579] (EE) Server terminated with error (1). Closing log file.