Here's a list of all original stock ROM firmware package for LG Optimus GT540 also known as LG GT540 Swift, LG Loop GT540. The firmware below were arrange according to their designated region/countries origin.
Note: the LG Optimus GT540 Original stock release is Android OS, v1.6 (Donut), and it is upgradable to froyo and gingerbread.
Firmware version list according to region or countries
GT540
ALGERIA, IRAQ
DZ_GT540AT-00-V10b-IRQ-XX-JUL-08-2010
AUSTRALIA
DZ_GT540AT-00-V20d-505-XX-DEC-08-2010
BALTIC REGION
DZ_GT540AT-00-V20d-BAL-XXX-DEC-02-2010
BH TELECOM BOSNIA
DZ_GT540AT-00-V10d-APP-XX-JUN-30-2010+0
BOUYGUES FRANCE
DZ_GT540AT-00-V20c-BYT-FR-FEB-09-2011
BELGIUM, CZECH, NETHERLANDS
DZ_GT540AT-00-V20b-EUR-XX-DEC-16-2010+0
BTC BULGARIA
DZ_GT540AT-00-V20b-284-03-DEC-15-2010+0
CHINA
GT540AT-00-V10c-OPEN-CHN-MAY-28-2010+0_DZ
CIS REGION
DZ_GT540AT-00-V20d-CIS-XXX-DEC-02-2010
ERA POLAND
DZ_GT540AT-00-V20a-260-02-DEC-09-2010+0
EIRCOM IRELAND, METEOR IRELAND
DZ_GT540AT-00-V20a-272-03-DEC-13-2010+0
ERONET BOSNIA
DZ_GT540AT-01-V10e-218-03-MAY-20-2010+0
EURO OPEN, GREECE, HUNGARY, M-TEL BULGARIA, PANNON HUNGARY, TELE2 CROATIA
DZ_GT540AT-00-V20b-APP-XX-DEC-10-2010+0
FRANCE
DZ_GT540AT-00-V20c-208-XX-FEB-15-2011+0
GERMANY
DZ_GT540AT-00-V20a-262-XX-DEC-08-2010+0
HONG KONG
DZ_GT540AT-00-V20a-HKG-XX-DEC-06-2010+0
INDIA
DZ_GT540AT-00-V20c-IND-XX-DEC-03-2010
ITALY
DZ_GT540AT-00-V20b-222-XX-DEC-15-2010+0
MOROCCO
DZ_GT540AT-00-V10b-MOR-XX-JUN-11-2010
NRJ FRANCE
DZ_GT540AT-00-V20a-208-01-NRJ-JAN-13-2011+0
OPTUS AUSTRALIA
DZ_GT540AT-00-V20d-505-02-DEC-01-2010
OPTIMUS PORTUGAL
DZ_GT540AT-01-V10b-268-03-MAY-12-2010
O2 UK
DZ_GT540AT-00-V20b-234-10-DEC-08-2010+0
O2 IRELAND
DZ_GT540AT-00-V20a-272-02-DEC-05-2010+0
ORANGE FRANCE
DZ_GT540AT-00-V20b-ORF-FR-DEC-03-2010
ORANGE ROMANIA
DZ_GT540AT-00-V10d-EUR-XX-MAY-31-2010+0
ORANGE UK
DZ_GT540AT-00-V20b-ORU-GB-DEC-03-2010
ORANGE POLAND
DZ_GT540AT-00-V20b-ORP-PL-DEC-03-2010
ORANGE SLOVAKIA
DZ_GT540AT-00-V20b-ORS-SK-DEC-03-2010
PCC HONG KONG
DZ_GT540AT-00-V20a-454-19-OCT-01-2010+0
PORTUGAL
DZ_GT540AT-00-V20b-268-XX-DEC-16-2010+0
POLAND
DZ_GT540AT-00-V20c-APP-XX-MAR-14-2011+0
PLUS POLAND
DZ_GT540AT-00-V20a-260-01-DEC-08-2010+0
P4 POLAND
DZ_GT540AT-00-V20a-260-06-DEC-08-2010+0
ROMANIA
DZ_GT540AT-00-V20b-226-XX-DEC-15-2010+0
RUSSIA
DZ_GT540AT-00-V20d-RUS-XXX-DEC-02-2010
SFR FRANCE
DZ_GT540AT-00-V20b-SFR-FR-DEC-03-2010
SINGAPORE, PHILIPPINES, VIET NAM, THAILAND
DZ_GT540AT-00-V20c-XXX-XX-DEC-03-2010
SOUTH AFRICA
DZ_GT540AT-00-V20a-AFR-XX-OCT-19-2010
STARHUB SINGAPORE
DZ_GT540AT-00-V20b-525-05-OCT-12-2010
SWITZERLAND
DZ_GT540AT-00-V20b-EUZ-XX-DEC-08-2010+0
SLOVENIA
DZ_GT540AT-00-V20c-293-XX-DEC-07-2010+0
SPAIN
DZ_GT540AT-00-V20c-EUR-XX-APR-07-2011+0
TAIWAN MOBILE TAIWAN
DZ_GT540AT-00-V20a-466-97-DEC-16-2010+0
TAIWAN
DZ_GT540AT-00-V20b-TWN-XX-DEC-16-2010+0
TURKEY
DZ_GT540AT-00-V10b-286-XX-JUL-28-2010
T-MOBILE HUNGARY
DZ_GT540AT-00-V20b-216-30-DEC-30-2010+0
T-MOBILE SLOVAKIA
DZ_GT540AT-00-V20b-231-02-DEC-15-2010+0
TMN PORTUGAL
DZ_GT540AT-01-V20b-268-06-DEC-09-2010+0
TESCO UK
DZ_GT540AT-00-V20c-234-10-TSC-DEC-04-2010+0
TELEKOM SERBIA
DZ_GT540AT-00-V20a-220-03-JAN-07-2011+0
UAE
DZ_GT540AT-00-V10c-ARB-XX-SEP-02-2010
VIP CROATIA
DZ_GT540AT-01-V10b-219-10-MAY-21-2010
VODACOM SOUTH AFRICA
DZ_GT540AT-00-V10a-655-01-JUL-21-2010
VODAFONE GERMANY
DZ_GT540AT-00-V20a-VD2-DE-JAN-07-2011
UNITED KINGDOM
DZ_GT540AT-00-V20c-234-XX-DEC-09-2010+0
VIRGIN FRANCE
DZ_GT540AT-00-V20a-208-01-VMF-DEC-16-2010+0
VODAFONE AUSTRALIA
DZ_GT540AT-01-V20c-505-03-DEC-01-2010
VODAFONE NEWZEALAND
DZ_GT540AT-00-V20d-530-01-DEC-01-2010
VODAFONE UK
DZ_GT540AT-00-V20c-VDF-GB-DEC-15-2010+0
YOIGO SPAIN
DZ_GT540AT-01-V10b-214-04-MAY-26-2010
GT540f
TELSTRA AUSTRALIA
DZ_GT540fAT-00-V20a-TEL-AU-DEC-09-2010
TELCEL MEXICO
DZ_GT540fAT-00-V10a-TCL-MX-JUN-11-2010+7
CLARO BRAZIL
DZ_GT540fAT-00-V20a-CLR-BR-OCT-20-2010+1
VIVO BRAZIL
DZ_GT540fAT-00-V20a-VIV-BR-OCT-20-2010+1
3 AUSTRALIA
DZ_GT540fAT-01-V20d-505-06-DEC-08-2010
GT540g
CLARO CENTRAL AMERICA
GT540gAT-00-V10a-CAO-XXX-JUL-29-2010+2
TIGO CENTRAL AMERICA
GT540gAT-00-V10a-TGO-XXX-JUL-30-2010+3
CLARO CHILE
DZ_GT540gAT-00-V10a-730-03-JUL-29-2010+1
COSTA RICA
GT540gAT-00-V10a-712-XXX-SEP-24-2010+2
PERSONAL ARGENTINA
GT540gAT-00-V20a-722-34-DEC-28-2010+0
CLARO PERU
GT540gAT-00-V10a-716-10-SEP-28-2010+1
CLM PANAMA
DZ_GT540gAT-00-V10a-714-03-AUG-12-2010+1
PORTA ECUADOR
DZ_GT540gAT-00-V10a-740-01-JUL-30-2010+3
TELEFONICA ARGENTINA, TELEFONICA VENEZUELA
GT540gAT-00-V20a-SSV-XXX-JAN-28-2011+0
GT540GO
OPTUS AUSTRALIA
DZ_GT540GOAT-01-V20a-505-02-DEC-07-2010
VODAFONE NETHERLANDS
DZ_GT540GOAT-00-V20a-204-04-MAR-24-2011+0
GT540R
ROGERS CANANDA
DZ_GT540RAT-00-V20a-RGS-CA-DEC-11-2010
LG Optimus GT540 Firmware Update Procedure:
" Proceed at your own risk, we are not liable and take no responsibility how you use these files"
1. Downlaod LGDP2 V36 UMTS Setup and extract, go to LGDP2_31_INCLUDE_LGDP1_Setup folder and install the exe (use serial number). Now copy all the files from DOWNLOAD folder and paste on C:\DOWNLOAD (overwrite if needed).
2. Install LG United Modem Driver, connect the phone to PC through USB cable and let the drivers to be installed.
3. You'll need firmware in DZ format and the correct DLL for your model.
4. Open LGDP2_V36_UMTS from C:\DOWNLOAD, select UMTS in Division and click OK.
5. Select port (check Device Manager for LG USBModem Port number), you can set a range from easy select or select manually. Select DLL and select firmware in Downlaod Configuration. Click OK.
6. Click START in main window and connect the phone to USB cable in Emergency download mode(VOL-DOWN+PWR).
Biggest thanks to nasirahmed @XDA for sharing all of this files..
Note: the LG Optimus GT540 Original stock release is Android OS, v1.6 (Donut), and it is upgradable to froyo and gingerbread.
Firmware version list according to region or countries
GT540
ALGERIA, IRAQ
DZ_GT540AT-00-V10b-IRQ-XX-JUL-08-2010
AUSTRALIA
DZ_GT540AT-00-V20d-505-XX-DEC-08-2010
BALTIC REGION
DZ_GT540AT-00-V20d-BAL-XXX-DEC-02-2010
BH TELECOM BOSNIA
DZ_GT540AT-00-V10d-APP-XX-JUN-30-2010+0
BOUYGUES FRANCE
DZ_GT540AT-00-V20c-BYT-FR-FEB-09-2011
BELGIUM, CZECH, NETHERLANDS
DZ_GT540AT-00-V20b-EUR-XX-DEC-16-2010+0
BTC BULGARIA
DZ_GT540AT-00-V20b-284-03-DEC-15-2010+0
CHINA
GT540AT-00-V10c-OPEN-CHN-MAY-28-2010+0_DZ
CIS REGION
DZ_GT540AT-00-V20d-CIS-XXX-DEC-02-2010
ERA POLAND
DZ_GT540AT-00-V20a-260-02-DEC-09-2010+0
EIRCOM IRELAND, METEOR IRELAND
DZ_GT540AT-00-V20a-272-03-DEC-13-2010+0
ERONET BOSNIA
DZ_GT540AT-01-V10e-218-03-MAY-20-2010+0
EURO OPEN, GREECE, HUNGARY, M-TEL BULGARIA, PANNON HUNGARY, TELE2 CROATIA
DZ_GT540AT-00-V20b-APP-XX-DEC-10-2010+0
FRANCE
DZ_GT540AT-00-V20c-208-XX-FEB-15-2011+0
GERMANY
DZ_GT540AT-00-V20a-262-XX-DEC-08-2010+0
HONG KONG
DZ_GT540AT-00-V20a-HKG-XX-DEC-06-2010+0
INDIA
DZ_GT540AT-00-V20c-IND-XX-DEC-03-2010
ITALY
DZ_GT540AT-00-V20b-222-XX-DEC-15-2010+0
MOROCCO
DZ_GT540AT-00-V10b-MOR-XX-JUN-11-2010
NRJ FRANCE
DZ_GT540AT-00-V20a-208-01-NRJ-JAN-13-2011+0
OPTUS AUSTRALIA
DZ_GT540AT-00-V20d-505-02-DEC-01-2010
OPTIMUS PORTUGAL
DZ_GT540AT-01-V10b-268-03-MAY-12-2010
O2 UK
DZ_GT540AT-00-V20b-234-10-DEC-08-2010+0
O2 IRELAND
DZ_GT540AT-00-V20a-272-02-DEC-05-2010+0
ORANGE FRANCE
DZ_GT540AT-00-V20b-ORF-FR-DEC-03-2010
ORANGE ROMANIA
DZ_GT540AT-00-V10d-EUR-XX-MAY-31-2010+0
ORANGE UK
DZ_GT540AT-00-V20b-ORU-GB-DEC-03-2010
ORANGE POLAND
DZ_GT540AT-00-V20b-ORP-PL-DEC-03-2010
ORANGE SLOVAKIA
DZ_GT540AT-00-V20b-ORS-SK-DEC-03-2010
PCC HONG KONG
DZ_GT540AT-00-V20a-454-19-OCT-01-2010+0
PORTUGAL
DZ_GT540AT-00-V20b-268-XX-DEC-16-2010+0
POLAND
DZ_GT540AT-00-V20c-APP-XX-MAR-14-2011+0
PLUS POLAND
DZ_GT540AT-00-V20a-260-01-DEC-08-2010+0
P4 POLAND
DZ_GT540AT-00-V20a-260-06-DEC-08-2010+0
ROMANIA
DZ_GT540AT-00-V20b-226-XX-DEC-15-2010+0
RUSSIA
DZ_GT540AT-00-V20d-RUS-XXX-DEC-02-2010
SFR FRANCE
DZ_GT540AT-00-V20b-SFR-FR-DEC-03-2010
SINGAPORE, PHILIPPINES, VIET NAM, THAILAND
DZ_GT540AT-00-V20c-XXX-XX-DEC-03-2010
SOUTH AFRICA
DZ_GT540AT-00-V20a-AFR-XX-OCT-19-2010
STARHUB SINGAPORE
DZ_GT540AT-00-V20b-525-05-OCT-12-2010
SWITZERLAND
DZ_GT540AT-00-V20b-EUZ-XX-DEC-08-2010+0
SLOVENIA
DZ_GT540AT-00-V20c-293-XX-DEC-07-2010+0
SPAIN
DZ_GT540AT-00-V20c-EUR-XX-APR-07-2011+0
TAIWAN MOBILE TAIWAN
DZ_GT540AT-00-V20a-466-97-DEC-16-2010+0
TAIWAN
DZ_GT540AT-00-V20b-TWN-XX-DEC-16-2010+0
TURKEY
DZ_GT540AT-00-V10b-286-XX-JUL-28-2010
T-MOBILE HUNGARY
DZ_GT540AT-00-V20b-216-30-DEC-30-2010+0
T-MOBILE SLOVAKIA
DZ_GT540AT-00-V20b-231-02-DEC-15-2010+0
TMN PORTUGAL
DZ_GT540AT-01-V20b-268-06-DEC-09-2010+0
TESCO UK
DZ_GT540AT-00-V20c-234-10-TSC-DEC-04-2010+0
TELEKOM SERBIA
DZ_GT540AT-00-V20a-220-03-JAN-07-2011+0
UAE
DZ_GT540AT-00-V10c-ARB-XX-SEP-02-2010
VIP CROATIA
DZ_GT540AT-01-V10b-219-10-MAY-21-2010
VODACOM SOUTH AFRICA
DZ_GT540AT-00-V10a-655-01-JUL-21-2010
VODAFONE GERMANY
DZ_GT540AT-00-V20a-VD2-DE-JAN-07-2011
UNITED KINGDOM
DZ_GT540AT-00-V20c-234-XX-DEC-09-2010+0
VIRGIN FRANCE
DZ_GT540AT-00-V20a-208-01-VMF-DEC-16-2010+0
VODAFONE AUSTRALIA
DZ_GT540AT-01-V20c-505-03-DEC-01-2010
VODAFONE NEWZEALAND
DZ_GT540AT-00-V20d-530-01-DEC-01-2010
VODAFONE UK
DZ_GT540AT-00-V20c-VDF-GB-DEC-15-2010+0
YOIGO SPAIN
DZ_GT540AT-01-V10b-214-04-MAY-26-2010
GT540f
TELSTRA AUSTRALIA
DZ_GT540fAT-00-V20a-TEL-AU-DEC-09-2010
TELCEL MEXICO
DZ_GT540fAT-00-V10a-TCL-MX-JUN-11-2010+7
CLARO BRAZIL
DZ_GT540fAT-00-V20a-CLR-BR-OCT-20-2010+1
VIVO BRAZIL
DZ_GT540fAT-00-V20a-VIV-BR-OCT-20-2010+1
3 AUSTRALIA
DZ_GT540fAT-01-V20d-505-06-DEC-08-2010
GT540g
CLARO CENTRAL AMERICA
GT540gAT-00-V10a-CAO-XXX-JUL-29-2010+2
TIGO CENTRAL AMERICA
GT540gAT-00-V10a-TGO-XXX-JUL-30-2010+3
CLARO CHILE
DZ_GT540gAT-00-V10a-730-03-JUL-29-2010+1
COSTA RICA
GT540gAT-00-V10a-712-XXX-SEP-24-2010+2
PERSONAL ARGENTINA
GT540gAT-00-V20a-722-34-DEC-28-2010+0
CLARO PERU
GT540gAT-00-V10a-716-10-SEP-28-2010+1
CLM PANAMA
DZ_GT540gAT-00-V10a-714-03-AUG-12-2010+1
PORTA ECUADOR
DZ_GT540gAT-00-V10a-740-01-JUL-30-2010+3
TELEFONICA ARGENTINA, TELEFONICA VENEZUELA
GT540gAT-00-V20a-SSV-XXX-JAN-28-2011+0
GT540GO
OPTUS AUSTRALIA
DZ_GT540GOAT-01-V20a-505-02-DEC-07-2010
VODAFONE NETHERLANDS
DZ_GT540GOAT-00-V20a-204-04-MAR-24-2011+0
GT540R
ROGERS CANANDA
DZ_GT540RAT-00-V20a-RGS-CA-DEC-11-2010
LG Optimus GT540 Firmware Update Procedure:
" Proceed at your own risk, we are not liable and take no responsibility how you use these files"
1. Downlaod LGDP2 V36 UMTS Setup and extract, go to LGDP2_31_INCLUDE_LGDP1_Setup folder and install the exe (use serial number). Now copy all the files from DOWNLOAD folder and paste on C:\DOWNLOAD (overwrite if needed).
2. Install LG United Modem Driver, connect the phone to PC through USB cable and let the drivers to be installed.
3. You'll need firmware in DZ format and the correct DLL for your model.
4. Open LGDP2_V36_UMTS from C:\DOWNLOAD, select UMTS in Division and click OK.
5. Select port (check Device Manager for LG USBModem Port number), you can set a range from easy select or select manually. Select DLL and select firmware in Downlaod Configuration. Click OK.
6. Click START in main window and connect the phone to USB cable in Emergency download mode(VOL-DOWN+PWR).
Biggest thanks to nasirahmed @XDA for sharing all of this files..