FM Ver 4.37.1507, erases unused flash memory irrespective of selection

[prabul]

I have used sectors at starting address FE00 and FE80 to store nonvolatile In Application Pragrammable data. IAP works fine, but when I used FM to upload the application with an upgrade, the nonvolatile IAP data is erased, though I have selected only "Erase blocks used by HEX File" selection. The "Erase all flash" option was deselected. I also confirmed that the hex file of the loaded application does not have any entry above address 0x4000.

Could you also please update us on the data variables used by IAP low level routines. In Philips technical note "TN06007" titled  "V51RX2 Migration" para 7 it is indicated that the IAP routines of the P89V51Rx uses direct data memory 0x20 and 0x30 thru 0x32. However it is silent if the user application needs to avoid these data memory or are these memory locations being pushed into stack by the IAP routines before their use, so that the user data is not corrupted by IAP.

Your support would be highly appreciated.

Prabul