I am converting a project built on an STM32F072 to an STM32L071. I use a small area of flash memory to store some tables, etc. < 100 bytes. The program using the STM32IDE works fine for the F072, but I get a Hard fault with the L071.

[LBarn.2]

I am using page erase and HAL flash program functions

[Tesla DeLorean]

Not really much detail to bite on there.

Does the L0 have width and alignment expectations?

Have a Hard Fault Handler that outputs some actionable data, look at the code faulting, look at the registers, and the address that's causing the issue.

[MM..1]

Maybe you use flash as eeprom code in F072, but addressing and size for L071 is other. Too L071 have internal EEPROM then better is use it instead flash writes.

[Andrew Neil]

Lots of info on debugging Hard Faults:

https://community.arm.com/developer/ip-products/system/f/embedded-forum/3257/debugging-a-cortex-m0-hard-fault

#HardFault​ 

[LBarn.2]

Thanks to MM..1, I used Data eeprom and it worked perfectly, Thanks!

[Andrew Neil]

[Uwe Bonnes]

While on STM32F, erased flash is 0xff. it is 0 on STM32L0. That could be a pitfall too.