All thinkpads have a Wifi card whitelist at the BIOS level that prevent installing certain WiFi cards. The restriction can be bypassed with a BIOS modification: either installing Libreboot, Coreboot or editing the official Lenovo/IBM BIOS.

Slot:	00:00.0
Class:	Host bridge [0600]
Vendor:	Intel Corporation [8086]
Device:	440BX/ZX/DX - 82443BX/ZX/DX Host bridge [7190]
Rev:	03

Slot:	00:01.0
Class:	PCI bridge [0604]
Vendor:	Intel Corporation [8086]
Device:	440BX/ZX/DX - 82443BX/ZX/DX AGP bridge [7191]
Rev:	03

Slot:	00:02.0
Class:	CardBus bridge [0607]
Vendor:	Texas Instruments [104c]
Device:	PCI1450 [ac1b]
SVendor:	IBM [1014]
SDevice:	ThinkPad 600X/A21m/T20/T22 [0130]
Rev:	03

Slot:	00:02.1
Class:	CardBus bridge [0607]
Vendor:	Texas Instruments [104c]
Device:	PCI1450 [ac1b]
SVendor:	IBM [1014]
SDevice:	ThinkPad 600X/A21m/T20/T22 [0130]
Rev:	03

Slot:	00:03.0
Class:	Ethernet controller [0200]
Vendor:	Intel Corporation [8086]
Device:	82557/8/9/0/1 Ethernet Pro 100 [1229]
SVendor:	Intel Corporation [8086]
SDevice:	EtherExpress PRO/100 SP Mobile Combo Adapter [2205]
Rev:	0c

Slot:	00:03.1
Class:	Serial controller [0700]
Vendor:	Agere Systems [11c1]
Device:	LT WinModem [045c]
SVendor:	Intel Corporation [8086]
SDevice:	Device [2205]
Rev:	01

Slot:	00:05.0
Class:	Multimedia audio controller [0401]
Vendor:	Cirrus Logic [1013]
Device:	CS 4614/22/24/30 [CrystalClear SoundFusion Audio Accelerator] [6003]
SVendor:	IBM [1014]
SDevice:	ThinkPad 600X/A20m [0153]
Rev:	01

Slot:	00:07.0
Class:	Bridge [0680]
Vendor:	Intel Corporation [8086]
Device:	82371AB/EB/MB PIIX4 ISA [7110]
Rev:	02

Slot:	00:07.1
Class:	IDE interface [0101]
Vendor:	Intel Corporation [8086]
Device:	82371AB/EB/MB PIIX4 IDE [7111]
Rev:	01
ProgIf:	80

Slot:	00:07.2
Class:	USB Controller [0c03]
Vendor:	Intel Corporation [8086]
Device:	82371AB/EB/MB PIIX4 USB [7112]
Rev:	01

Slot:	00:07.3
Class:	Bridge [0680]
Vendor:	Intel Corporation [8086]
Device:	82371AB/EB/MB PIIX4 ACPI [7113]
Rev:	03

Slot:	01:00.0
Class:	VGA compatible controller [0300]
Vendor:	S3 Inc. [5333]
Device:	86C270-294 Savage/IX-MV [8c12]
SVendor:	IBM [1014]
SDevice:	ThinkPad T20/T22 [017f]
Rev:	13

00:00.0 Host bridge [0600]: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX Host bridge [8086:7190] (rev 03)
	Kernel driver in use: agpgart-intel
00:01.0 PCI bridge [0604]: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX AGP bridge [8086:7191] (rev 03)
	Kernel modules: shpchp
00:02.0 CardBus bridge [0607]: Texas Instruments PCI1450 [104c:ac1b] (rev 03)
	Subsystem: IBM ThinkPad 600X/A21m/T20/T22 [1014:0130]
	Kernel driver in use: yenta_cardbus
	Kernel modules: yenta_socket
00:02.1 CardBus bridge [0607]: Texas Instruments PCI1450 [104c:ac1b] (rev 03)
	Subsystem: IBM ThinkPad 600X/A21m/T20/T22 [1014:0130]
	Kernel driver in use: yenta_cardbus
	Kernel modules: yenta_socket
00:03.0 Ethernet controller [0200]: Intel Corporation 82557/8/9/0/1 Ethernet Pro 100 [8086:1229] (rev 0c)
	Subsystem: Intel Corporation EtherExpress PRO/100 SP Mobile Combo Adapter [8086:2205]
	Kernel driver in use: e100
	Kernel modules: e100
00:03.1 Serial controller [0700]: Agere Systems LT WinModem [11c1:045c] (rev 01)
	Subsystem: Intel Corporation Device [8086:2205]
	Kernel driver in use: serial
00:05.0 Multimedia audio controller [0401]: Cirrus Logic CS 4614/22/24/30 [CrystalClear SoundFusion Audio Accelerator] [1013:6003] (rev 01)
	Subsystem: IBM ThinkPad 600X/A20m [1014:0153]
	Kernel modules: snd-cs46xx
00:07.0 Bridge [0680]: Intel Corporation 82371AB/EB/MB PIIX4 ISA [8086:7110] (rev 02)
00:07.1 IDE interface [0101]: Intel Corporation 82371AB/EB/MB PIIX4 IDE [8086:7111] (rev 01)
	Kernel driver in use: ata_piix
00:07.2 USB Controller [0c03]: Intel Corporation 82371AB/EB/MB PIIX4 USB [8086:7112] (rev 01)
	Kernel driver in use: uhci_hcd
00:07.3 Bridge [0680]: Intel Corporation 82371AB/EB/MB PIIX4 ACPI [8086:7113] (rev 03)
	Kernel modules: i2c-piix4
01:00.0 VGA compatible controller [0300]: S3 Inc. 86C270-294 Savage/IX-MV [5333:8c12] (rev 13)
	Subsystem: IBM ThinkPad T20/T22 [1014:017f]
	Kernel modules: savagefb