Editing Flash memory (section)

===X-ray effects===
Most flash ICs come in [[ball grid array]] (BGA) packages, and even the ones that do not are often mounted on a PCB next to other BGA packages. After [[PCB Assembly]], boards with BGA packages are often X-rayed to see if the balls are making proper connections to the proper pad, or if the BGA needs [[rework (electronics)|rework]]. These X-rays can erase programmed bits in a flash chip (convert programmed "0" bits into erased "1" bits). Erased bits ("1" bits) are not affected by X-rays.<ref>
Richard Blish.
[http://www.spansion.com/Support/Application%20Notes/Dose_Minimization_Xray_Inspect_AN.pdf "Dose Minimization During X-ray Inspection of Surface-Mounted Flash ICs"] {{webarchive|url=https://web.archive.org/web/20160220204227/http://www.spansion.com/Support/Application%20Notes/Dose_Minimization_Xray_Inspect_AN.pdf |date=20 February 2016 }}.
p. 1.
</ref><ref>
Richard Blish.
[http://www.spansion.com/Support/Application%20Notes/X-ray_inspection_on_flash_AN.pdf "Impact of X-Ray Inspection on Spansion Flash Memory"] {{webarchive|url=https://web.archive.org/web/20160304044211/http://www.spansion.com/Support/Application%20Notes/X-ray_inspection_on_flash_AN.pdf |date=4 March 2016 }}
</ref>

Some manufacturers are now making X-ray proof SD<ref>{{cite web |url= https://www.sandisk.com/home/memory-cards/sd-cards/extremepro-sd-uhs-i |title= SanDisk Extreme PRO SDHC/SDXC UHS-I Memory Card |access-date= 2016-02-03 |url-status= live |archive-url= https://web.archive.org/web/20160127214859/https://www.sandisk.com/home/memory-cards/sd-cards/extremepro-sd-uhs-i |archive-date= 27 January 2016}}</ref> and USB<ref>{{cite web |url= http://www.samsung.com/us/computer/memory-storage-accessories/MUF-32BB/AM |title= Samsung 32GB USB 3.0 Flash Drive FIT MUF-32BB/AM |access-date= 2016-02-03 |url-status= live |archive-url= https://web.archive.org/web/20160203145010/http://www.samsung.com/us/computer/memory-storage-accessories/MUF-32BB/AM |archive-date= 3 February 2016}}</ref> memory devices.